[2019-11-22]从地理上看，哪个国家是最难被入侵的？

Uriel Moore , Veteran, and majored in history. Makes sense I like this topic...
My top 3.
1. Vietnam.
They have been punching faces since Rome was around. They beat the Chinese, the French, and the USA. In that order. These are people no one should fuck with, then add in brutal terrain, it's easy to understand why a land war even with air superiority there would end in disaster for any invading army.
2. Afghanistan.
When military geniuses like Alexander and Genghis fucking Kahn say "screw that, not worth it" take heed people. Not really a country but a bunch of heavily armed tribes that frown upon invading megalomaniacs, Afghanistan has been a meat grinder for invading armies for thousands of years. Technology or badass commanders means nothing. The Soviet Union got their asses spanked unceremoniously. The USA today remains bogged down there with no victory in sight. Let me reiterate: Ghenghis Kahn, a guy that created an empire that dwarfed Rome, came, saw, and got the hell out of there rather than deal with pissed off mountain dwelling tribal insurgents.

Uriel Moore ，老兵，主修历史。
我的前三名是以下：
1. 越南。
自从罗马时代以来，他们就开始打仗了。他们击败了中国、法国和美国。这些人是不应该惹的人，然后加上原始的地形，很容易理解为什么一场陆地战争即使他们拥有空中优势，也会在入侵上以灾难的失败而告终。
2. 阿富汗。
当像亚历山大和成吉思汗这样的军事天才说“去他妈的，不值得”的时候，我们就要注意了。阿富汗不是一个真正的国家，而是一群全副武装的部落，他们反对那些自大的侵略者，几千年来，阿富汗一直是入侵者的绞肉机。技术或者糟糕的指挥官都不算什么。苏联已经尝到了苦头。今天的美国仍然在那里陷入困境，看不到胜利的曙光。 让我重申一遍: 成吉思汗，一个创造了让罗马都相形见绌的帝国的家伙，来到这里了，看了一眼，然后就离开了，而不是去处理那些愤怒的原始部落起义者。

3. Russia. Forget the endless supply of troops who are not above brutal tactics to get the job done. The infamous Russian winter has wiped out literally millions of invading troops. Charles XII of Sweden was the first to learn this lesson when he invaded Russia and was soundly wrecked by Peter the Great . Napoleon ignored Sweden's debacle, invaded Russia, and got the Grand Armee wiped the hell out. Which would eventually lead to his downfall. Over 93 percent of the French army never made it back from Russia. Hitler apparently also ignored the history books and was welcomed to the Soviet Union by none other than Uncle Joe Stalin. Again, with another assist from the Russian winter, the Germans lost millions of soldiers. Hundreds of thousands more that were foolish enough to surrender were taken to even more brutally cold shitholes like Siberia where they were starved to death or turned into ice cubes.
Honorable mention:
The USA.
First, the vast and diverse terrian is a deterrent in itself. Add in the fact that there are more guns than people in the USA. Even if an invading army somehow was able to get past our military, a heavily armed domestic insurgency would make any invader pay miserably, as a modern superpower, any invading army would be wiped out. The American Civil War not only cost the country 600,000 lives, but with ironclad navies, gatling guns, and hardcore commanders, it was a final exclamation point to the rest of the world that the USA was effectively invasion-proof.

3.俄罗斯。忘记那些为了完成任务而不惜采取野蛮的人海战术的军队吧。声名狼藉的俄罗斯冬天几乎消灭了数百万入侵军队。卡尔十二世是第一个学到这个教训的，当他入侵俄罗斯时，被彼得大帝彻底摧毁了。拿破仑无视瑞典的溃败，入侵俄国，让大军全军覆没了。这最终导致了他的垮台。超过93% 的法国军队未从俄罗斯返回。希特勒显然也忽略了历史教训，苏联欢迎他的不是别人，正是斯大林大叔。再一次在俄罗斯冬天的帮助下，德国失去了数百万士兵。还有成千上万愚蠢到投降的人被带到西伯利亚这样更加寒冷的地方，在那里他们要么被饿死，要么被冻成冰块。
荣誉奖：美国。
首先，巨大而多样化的地形本身就是一种威慑。再加上在美国枪支比人口还多这个事实。 即使一支入侵军队以某种方式通过了我们的军事检查，一场全副武装的国内叛乱也会让任何入侵者付出惨痛的代价。作为一个现代超级大国，任何入侵的军队都会被消灭。 美国内战不仅夺去了60万人的生命，还有装甲舰的海军、加特林机关枪和核心指挥官，这是美国向世界其他国家发出的最后一个叹号：美国能有效抵御入侵证明。

S Neale
Afghanistan, where Empires go to die.
Before getting to my answer I would like to state that the question says "geographically" not "militarily".. My answer focuses on two things:
* The Afghani Physical Geography - Afghanistan is a mix of deadly environments.
* The Afghani People, who represent part of Afghanistan's Geography.
Afghanistan is well known for it's rugged nature, and has been the center point of several wars, I am not going to be focusing on the reasons behind those conflicts but rather, what happened during the conflicts.
Okay so here is Afghanistan which according to Wikipedia is:
" A landlocked mountainous country with plains in the north and southwest, Afghanistan is located within South Asia and Central Asia. It is part of the US-coined Greater Middle East Muslim world, which lies between latitudes 29° N and 39° N, and longitudes 60° E and 75° E. The country's highest point is Noshaq, at 7,492 m (24,580 ft) above sea level. It has a continental climate with harsh winters in the central highlands, the glaciated northeast (around Nuristan), and the Wakhan Corridor, where the average temperature in January is below −15 °C (5 °F), and hot summers in the low-lying areas of the Sistan Basin of the southwest, the Jalalabad basin in the east, and the Turkestan plains along the Amu River in the north, where temperatures average over 35 °C (95 °F) in July."

S Neale
阿富汗，帝国坟场。
在我回答这问题之前，我想说这个问题是“地理上的”而不是“军事上的”。我的回答主要在亮点：
* 阿富汗的自然地理——阿富汗是致命环境的混合体。
* 阿富汗的人们——他们代表了阿富汗地理的一部分。
阿富汗因其崎岖的自然环境而闻名，并且一直是几场战争的中心，我不打算关注这些冲突背后的原因，而是关注冲突期间发生的事情。
根据维基百科介绍的阿富汗:
阿富汗位于南亚和中亚，是一个北部和西南部有平原的内陆多山国家。它是美国创造的大中东穆斯林世界的一部分，位于北纬29度和北纬39度之间，东经60度和东经75度之间。 这个国家的最高点是诺沙克，海拔7492米(24580英尺)。 它属于大陆性气候，冬季严酷的地区包括中东西原、冰川覆盖的东北部(努里斯坦周围)和瓦罕走廊，那里一月份的平均气温低于 -15摄氏度(5华氏度) ，西南部锡斯坦盆地低洼地区、东部的贾拉拉巴德盆地和北部的阿姆河平原，夏季炎热，7月份平均气温超过35摄氏度(95华氏度)。”

Despite having numerous rivers and reservoirs, large parts of the country are dry. The endorheic Sistan Basin is one of the driest regions in the world. Aside from the usual rainfall, Afghanistan receives snow during the winter in the Hindu Kush and Pamir Mountains, and the melting snow in the spring season enters the rivers, lakes, and streams. However, two-thirds of the country's water flows into the neighboring countries of Iran, Pakistan, and Turkmenistan. The state needs more than US$2 billion to rehabilitate its irrigation systems so that the water is properly managed.
Alright, so I highlighted the interesting stuff, that being the diverse climate and landscape. Which means if you're planning on invading your forces better be versatile, like really versatile..Oh and to add to that, as if trekking across the country sounded bad to your troops, remember that you're dealing with an enemy who knows the terrain like the back of their hand.
Yes, that's Afghanistan..

尽管有许多河流和水库，这个国家的大部分地区是干旱的。 内陆西斯坦盆地是世界上最干旱的地区之一。 除了通常的降雨量，冬季的阿富汗，兴都库什山脉和帕米尔山会积雪，春季融化的雪会进入河流、湖泊和溪流。 然而，该国三分之二的水流入邻国伊朗、巴基斯坦和土库曼斯坦。该国需要超过20亿美元来恢复其灌溉系统，以便妥善管理水资源。
好吧，我强调了一些有意思的东西，那就是多样化的气候和地形。 这意味着如果你计划让军队入侵这个国家，你最好是多才多艺的人......哦，还有，如果你的部队觉得徒步穿越这个国家听起来很糟糕，请记住，你面对的敌人对地形了如指掌。
是的，那就是阿富汗...

Derrick Patterson , B.A History, Bates College (2013)
There are quite a few locations that would prove difficult to invade; however, the top countries would be:
China
If you find the idea of fighting over a billion people daunting, then you should avoid invading China at all costs. 1.3 billion (that’s the entire US population plus an additional billion people. This is not to say that China’s entire population base is armed and ready for an attack. However, in the event of an invading force, it would not take long for the government to start handing out weapons and encouraging the people to form a united front.
If you are courageous enough to push forward despite these numbers, then you would have to deal with China’s sheer size. Diverse climates, diverse terrain, and oceans on all sides. Invaders would have to prepare themselves for the Gobi Desert, the jungles of Southeast Asia, and snowy Himalayan regions all of which would make air support challenging to sustain.
Russia

Derrick Patterson 、贝茨学院历史学士(2013)
事实证明，有相当多的地方是难以入侵的；然而，排名最靠前的国家是：
中国
如果你觉得和十亿人战斗的想法令人畏惧，那么你应该不惜一切代价避免入侵中国。13亿(这是美国全部人口加上另外10亿人口)。 虽然这并不是说中国的整个人口都已经武装起来准备好迎接攻击。但是，一旦发生侵略，政府很快就会开始发放武器，鼓励人民形成统一战线。
如果你有足够的勇去面对这庞大的数字，那么你将不得不面对中国庞大的领土规模。不同的气候，不同的地形，四面八方的海洋。入侵者将不得不在戈壁沙漠、东南亚丛林和喜马拉雅山雪域做好准备，所有这些地形都将让空中支援难以维持。

As history has taught us (through Sweden, Germany, and France), one thing you NEVER do in war is invade Russia. The country’s vast landscape and incredibly harsh winter is enough to bring even the mightiest armies to their knees. We are talking about some of the world’s biggest temperature changes, reaching as cold as -90 degree (F), and as high as 113.7 degrees (F).
If that is not enough to discourage an invading enemy then the 6.6 million square miles will. Endless mountains and wilderness essentially serving as perfect hiding spots for a Russian Army base or perhaps a group of overly patriotic citizens. Combine that with over 766,000 military personnel, 15, 400 tanks, 1,750 helicopters, and 751 air fighters, and your goals of conquering the country and holding on to it have just become impossible to achieve.

俄罗斯
历史告诉我们(通过瑞典、德国和法国) ，在战争中绝不能入侵俄罗斯。 这个国家幅员辽阔，冬天的寒冷令人难以置信，足以让最强大的军队屈服。我们正在谈论的是世界上最大的温度变化，最低达到零下90度(华氏) ，最高达到113.7度(华氏)。
如果这还不足以阻止入侵的敌人，那么这660万平方英里的土地将会令入侵难以进行。 无尽的山脉和荒野，本质上是俄罗斯军事基地或者一群狂热爱国者的完美藏身之处。再加上超过766,000名军事人员，15,400辆坦克，1750架直升机和751架空中战斗机，你征服这个国家并坚持下去的目标已经变得不可能实现了。

The first major obstacle would be getting past the US military which is near impossible in and of itself. The US spends about $600 billion on its military might, making up a third of the world’s military spending. They are equipped with 1,400,000 active personnel, 8,850 tanks, 7,100 helicopters, 2,300 air fighters, 7,100 nuclear warheads, and one of the strongest navies in the world. Assuming you made it to the coast from the East or West, you would be met with much fire and fury the moment you stepped foot on US soil.
The United States is probably the most geographically diverse country in the world. Vast expanses of countryside, densely forested mountains and scorching deserts are sure to complicate any efforts of invasion.
If you somehow were able to overcome this then you would have to deal with US citizens. Because of the second amendment, most are equipped with their own personal firearms and are more than willing to use them if they feel threatened by a foreign enemy. This is especially the case in southern (red) states.
Australia

美国
第一个主要障碍将是跨过美国军队，这本身几乎是不可能的。 美国在军事力量上花费了大约6000亿美元，占世界军事开支的三分之一。 他们拥有140万现役人员，8850辆坦克，7100架直升机，2300架战斗机，7100枚核弹头，以及世界上最强大的海军之一。假设你从东部或西部到达了海岸，那么当你踏上美国的土地时，你将会遭到猛烈的炮火和怒火。
美国可能是世界上地理分布最多样化的国家。 广阔的乡村，茂密的森林山脉和灼热的沙漠肯定会使任何入侵行动复杂化。
如果你以某种方式能够克服这一点，那么你将不得不与美国公民打交道。 由于宪法第二修正案的规定，大多数人都配备了自己的轻兵器，如果他们感到受到外国敌人的威胁，他们会更愿意使用这些武器。 南方(红色)州尤其如此。

It should come to no surprise that Austrailia is essentially a continent in and of itself. With over 3 million square miles of desert, an extensive Coral Barrier Reef, 60,000 active personnel and another 44,000 on reserve, the country would prove almost impossible to successfully conquer for any would-be invader. Australia’s isolated position in the Oceania region allows the army to flex its naval strength (6 submarines, 2 aircraft carriers) and air-force (78 air fighters, 188 helicopters) while an unlucky enemy tries desperately to reach the coast; that’s assuming they have enough resources to make it.
Japan thought about invading Australia in WWII but realized that they would need over 200,000 men to deal with guerrilla warfare tactics from Australian citizens and soldiers and to traverse through a scorching outback home to a variety of dangerous animals and insects.
Japan

澳大利亚
澳大利亚本质上是一个大陆，这一点不足为奇。 这个国家有超过300万平方英里的沙漠，广阔的珊瑚礁，6万名现役军人和4.4万名预备役军人，任何潜在的入侵者几乎不可能成功征服。 澳大利亚在大洋洲地区的孤立位置使得军队可以发挥其海军力量(6艘潜艇，2艘航空母舰)和空军力量(78架空军战斗机，188架直升机) ，当不幸的敌人拼命想要到达海岸时，这还是假设他们有足够的资源来实现这一目标。
日本曾考虑在二战中入侵澳大利亚，但是他们意识到他们需要超过20万人来应对澳大利亚公民和士兵的游击战，还要穿越灼热的内陆，进入各种危险的动物和昆虫的家园。

Being an island-nation is one of Japan’s greatest strength (Just ask the Mongols). This speaks volumes of how successful Japan has been in defending its country. However, in addition to that Japan has grown a sizable army, with a budget that ’s currently ranked sixth in the world. Trying to reach the coast would prove incredibly difficult and would require a very long line of resources.
Japan’s military expansion was influenced by troubles arising over the South China Sea. They are equipped with over 250,000 active personnel, 777 tanks, 289 air fighters, 741 helicopters, 17 submarines, and 3 aircraft carriers. If this is not enough firepower to discourage an invasion, know that you would not only be attacking Japan but also the United States. Under the Treaty of Mutual Cooperation and Security, the US and Japan have agreed to assist each other in the event of an armed attack on Japanese territory. Your goals of invasion have just become impossible to achieve or near impossible. Please also remember that the words submit and surrender do not apply to the Japanese during times of war.

日本
作为一个岛国是日本最大的优势之一(只要问问蒙古人就知道了)。这充分说明了日本在保卫自己国家方面是多么成功。然而，除此之外，日本还增发展了一支规模可观的军队，其预算目前排名世界第六。试图到达海岸是难以置信的困难，并需要一条非常长的资源线。
日本的军事扩张受到南中国海问题的影响。 他们装备了超过250,000名现役人员，777辆坦克，289架空中战斗机，741架直升机，17艘潜艇和3艘航空母舰。如果这些火力还不足以阻止入侵，那么要知道你们不仅是攻击日本，也是在攻击美国。 根据《美日安保条约》 ，美国和日本同意在领土遭到武装攻击时提供互相协助。你的入侵目标已经变得不可能实现了。还请记住，投降和任何投降的字眼在战争期间不适用于日本人。

Bas Leijser , Writer, mountaineer, coffee addict, engineer
The Netherlands!
Yes, you read that right.
Our army is in a rather sad state right now:
* 60,000 active personnel
* 5000 reserves
* A whopping 16 tanks (beat that Russia!)
* Yearly budget of 8 billion (1.33% of USA’s budget)
We were once the most powerful country in the world (and, sadly, one of the leading countries in slavery and colonialism) but now we are just a cute little dot on the map.
We had close to 1000 tanks in 1990 (the Leopard 2) but the government has sold all of them ever since.
And still, I dare say that our country is the most difficult to invade.
Perhaps I really should not be giving away our secret. This is what would happen if, say, Russia would decide to invade us (purely hypothetical, might as well be USA or China).
Several thousand tanks roll into the Netherlands all across the eastern border. There is little resistance.
Within hours, half of the country is occupied. Our 16 tanks are nothing but wrecks.
The enemies push on, The only thing that gives them pause, is the heroic counter-attack by the 34th Bicycle Cavalry Force.
As the enemies near the capital of Amsterdam, the following conversation takes place in our army’s HQ:
General 1: “The Netherlands is doomed! Perhaps we should have learned our lesson when we cut our army budget right before WW2.”
General 2: “We have no choice now.”
General 1: “Yes, we proceed with the plan.”
Both generals: “Activate Project Atlantis.”
The following footage is highly classified, but let it serve as a warning to any potential invaders.
Initiation of Project Atlantis would look a little like this:
You may take our lives, but you will never take our homeland!
Since the Netherlands is the only country worldwide that is almost entirely below sea-level, it even has a plan where flooding the country is used as a defence strategy (Hollandic Water Line - Wikipedia) and this can easily be done by destroying various flood defences; I say we are the most difficult to invade because there will be nothing to invade if we are desperate enough.

Bas Leijser 作家，登山运动员，咖啡成瘾者，工程师
荷兰！
是的，你没看错。
我们的军队现在处于一种相当悲哀的状态:
* 60000现役人员
* 5000储备人员
* 多达16辆坦克(击败了俄罗斯!)
* 每年预算80亿元(占美国预算的1.33%)
我们曾经是世界上最强大的国家(不幸的是，我们是奴隶制和殖民主义的主要国家之一) ，但现在我们只是地图上的一个可爱的小点。
我们在1990年有将近1000辆坦克(豹2) ，但是从那以后政府就把它们全卖了。
不过，我敢说我们的国家是最难侵略的。也许我真的不应该泄露我们的秘密。 如果俄罗斯决定入侵我们(纯粹假设，也有可能是美国或中国) ，这就是将会发生的事情。
几千辆坦克越过东部边界开进荷兰，我们几乎没有抵抗。
几个小时之内，半个国家就被占领了。 我们的16辆坦克只剩下残骸之外什么都没有。
敌人向前推进，唯一使他们停下来的是第34骑兵团英勇的反击。
当敌人在首都阿姆斯特丹附近的时候，下面的对话会发生在我们军队的总部：
将军1: “荷兰完蛋了！或许我们应该吸取教训，在第二次世界大战前就削减军队预算。”
将军2: “我们现在别无选择。”
将军1: “是的，我们按计划进行。”
两位将军异口同声：“启动亚特兰蒂斯计划。”
下面的内容是高度机密的，但是这是它作为对任何潜在入侵者的警告。
亚特兰蒂斯计划的启动看起来有点像这样：
你可以夺走我们的生命，但你永远夺不走我们的家园！
由于荷兰是世界上唯一一个几乎完全低于海平面的国家，它甚至制定了一项计划，将洪水作为防御战略(荷兰水线-维基百科) ，而这可以很容易地通过摧毁各种防洪设施来实现；我说我们是最难入侵的国家，因为如果我们足够绝望，就不会有任何东西可以入侵我们。

Mohit Kapila , I know quite alot about China and India
I’m going to have to give this one to our rival, Australia.
As you may know, I am a Kiwi, but even I can’t deny that Australia should be noted as quite difficult to invade.
Australia is, in my opinion, a country that is unenviable by any other major country. Most of the major countries are thousands of kilometres away from Australia.
Distance between:
* Canberra-Washington DC: 15,962KM
* Canberra-Beijing: 9018KM
* Canberra-Brasilia: 14,075KM
* Canberra-New Delhi: 10,365KM
* Canberra-London: 17,001KM
* Canberra-Paris: 16,939KM
* Canberra-Moscow: 14,498KM
* Canberra-Wellington: 2329KM
* Canberra-Jakarta :5401km
The point I’m trying to make is that the Australian continent is quite far away from other civilization.
A country invading Australia would need an extremely powerful navy just to get near it. The only country that could actually do real damage to Australia is Indonesia, and even they are hundreds of kilometers away. And let’s admit it, New Zealand can’t really do much to Australia.

Mohit Kapila 我对中国和印度很了解
我要把这个回答交给我们的对手澳大利亚。
你可能知道，我是一个新西兰人，但是即使是我也不能否认澳大利亚很难被入侵。在我看来，澳大利亚是一个其他任何主要国家都不会去羡慕的国家。大多数主要国家都离澳大利亚有数千公里远。
距离:
* 堪培拉ー华盛顿: 15,962公里
* 坎培拉ー北京: 9018公里
* 堪培拉ー巴西利亚: 14075公里
* 堪培拉ー新德里: 10,365公里
* 堪培拉ー伦敦: 17,001公里
* 堪培拉ー巴黎: 16,939公里
* 堪培拉ー莫斯科: 14,498公里
* 坎培拉ー威灵顿: 2329公里
* 堪培拉ー雅加达: 5401公里
我想说的是，澳大利亚大陆与其他文明相距甚远。
一个入侵澳大利亚的国家需要一支非常强大的海军才能接近它。唯一能够真正对澳大利亚造成伤害的国家是印度尼西亚，而且他们距离澳大利亚有数百公里之遥。 我们得承认，新西兰对澳大利亚没法做太多事情。

Now that we have covered distance from other countries, let’s talk about the immense size of Australia. Australia is huge. I’m sure that even that is an understatement. Australia covers 7.692 million km2, or about 1.5% of Earth's surface!!
And if the animals don’t get you, then the intense climate will. During WW2, the Australians drew up a line called the Brisbane line, after the nearby large city. The line was drawn to show how far the Japanese could get into Australia before the climate killed them off.
Australia is just a place any invader will find hard to occupy.

既然我们已经谈到了与其他国家的距离，让我们来谈谈澳大利亚的巨大面积。澳大利亚幅员辽阔。我敢肯定，即使是这样也是轻描淡写的。澳大利亚占地769.2万平方公里，约占地球表面的1.5% ！如果动物没让你困扰，那么极端的气候就会。第二次世界大战期间，澳大利亚人在附近的大城市布里斯班划出了一条线，称为布里斯班线。这条线是为了显示日本人在气候杀死他们之前可以进入澳大利亚多远。
澳大利亚是一个任何入侵者都很难占领的地方。

Nadhiya Athaide , studied History at University of Mohaghegh Ardabili
China has only been fully conquered and invaded twice in human history. One by the Mongols (it took them over 40 years to conquer China) and the Japanese who had somewhat limited control over China. China geographically is uninhabited for hundreds of miles, is nearly covered in the Gobi desert and has plenty of mountains famous for their grand Buddhist Stupas And Temples. Even when Britain invaded China they were never fully able to control China. China is simply to big for any imperial power or force to tightly control.

Nadhiya Athaide ，在马哈盖大学学习历史
中国在人类历史上只被完全征服和入侵过两次。一次是蒙古人(他们用了40多年才征服中国) ，另一个是对中国有限控制的日本人。中国在地理上有数百英里无人居住，几乎被戈壁沙漠所覆盖，有许多山脉以其宏伟的佛塔和寺庙而闻名。即使英国入侵中国，他们也从未完全控制过中国。对于任何帝国主义强权或势力来说，中国太大了，无法做到严密控制。

Balaji Viswanathan, student of world history.
Japan. There has never been a foreign born person ruling the country in its history. Only the most powerful weapon ever - Atomic bomb - could make them surrender and even that was not enough for a full transfer of control. Even the Mongols failed there twice. Every other civilization has been invaded in the past. History of Japan
Why is Japan so hard to conquer?

Balaji Viswanathan 世界历史系的学生。
日本。 在这个国家的历史上，从来没有外国人来统治过这个国家。只有有史以来最强大的武器——原子弹，才能使他们投降，即使这样也不足以完全移交控制权。甚至连蒙古人也失败了两次。在过去，每一个其他文明都曾被入侵过。
为什么日本如此难以征服？

Islands are always hard to conquer and Japan's islands especially Honshu is among the largest island by population. It is not easy to conquer a population that has high emphasis on sustaining itself. New Zealand is an island too, but Japan has more than 25 times its population. It is easier to overpower the 4.4 million Kiwis than to do the same to 127 million Japanese.
Britain is an island too and has some of the advantages, but besides being a little smaller, it is far more closer to the mainland. Crossing the East China sea between Japan & China is far more harder than crossing the north sea or the English channel. Britain also has a number of powers surrounding it. In case of Japan, there is the frozen Siberia, the Korean peninsula and China being the only challenges. Korea is smaller, Russia cannot easily supply to Siberia and that leaves China as the only real threat - and they are a few hundred miles off the ocean.
In short, Japan is not just a massively populated island, but quite remote too.

岛屿总是很难被征服，日本的岛屿，尤其是本州，是世界上人口最多的岛屿之一。征服一个高度重视自给自足的民族并不容易。新西兰也是一个岛国，但日本的人口是其人口的25倍以上。 制服440万新西兰人要比制服1.27亿日本人容易得多。
英国也是一个岛屿，有一些优势，但除了小一点，它离大陆更近。在日本和中国之间穿越东海比穿越北海或英吉利海峡要困难得多。英国周围也有一些大国。 就日本而言，唯一的挑战就是冰封的西伯利亚、朝鲜半岛和中国。韩国比较小，俄罗斯不能轻易地向西伯利亚提供补给，这使得中国成为唯一真正的威胁——而且它们距离大洋只有几百英里。
简而言之，日本不仅是一个人口众多的岛屿，而且也相当偏远。

Compare that with Canada, whose population all live close to the US border and the US could just take over all the border cities with a lot less pain than taking over Japan. It also much smaller population [1/4 of Japan].
Britain also has historical fault lines between English & Scots - an alliance that could break apart [with a future referendum] and having two powers in the island can make things easier for an outside power. Japan is far more secure in that point - there are no major fault lines between its major islands.
Island + large population + remote location + history of non-submission = practically impossible to invade.

相比之下，加拿大的人口全部居住在美国边境附近，而美国可以接管所有的边境城市，比接管日本的痛苦要小得多。 它的人口也要少得多。
英格兰和苏格兰之间也存在历史断层——联盟可能会(在未来的公投中)分裂，岛上拥有两个大国可以让外部势力容易得逞。日本在这一点上要安全得多——它的岛屿之间没有主要的断层线。
岛屿 + 庞大的人口 + 偏远的地理位置 + 不屈服的历史，几乎不可能被入侵。

Akash Tanwar , works at Marvell Semiconductor
NEPAL.
It's a small landlocked country between a billion something Indians and a billion something Chinese. Since its landlocked, an amphibious invasion is ruled out.
Nepal lies almost entirely within the Himalayas.
It has Mt Everest. The highest mountain peak on earth.
So, to get to Nepal, you would have to maneuver your army over land either through India or through China.
Both are nuclear powers and each has a standing army of a million plus. During the last 75 years, both countries have fought several bloody wars including one against each other. So both countries have sufficient combat experience.
I don't think they would be too excited having an outside army just walk by their lands.
Let's say India does give march-by rights to you. China will be up in arms and will come to Nepal’s aid. Why? It would like to keep Nepal as a neutral buffer country and wouldn't want yet another army in its own backyard. Good luck dealing with an angry Chinese army.

Akash Tanwar 在Marvell半导体公司工作
尼泊尔。
这是在十亿左右印度人和十亿左右中国人之间的内陆国家。由于其被陆地包围，两栖入侵就不可能了。尼泊尔几乎完全位于喜马拉雅山脉之内。它有珠穆朗玛峰，世界上最高的山峰。
所以，要到达尼泊尔，你必须让你的军队通过印度或者中国。
这两个国家都是核大国，都有一支超过一百万人的常备军。 在过去的75年里，两国都经历了几次血腥的战争，其中包括一次相互之间的战争。所以两国都有足够的作战经验。
如果有一支外来军队经过他们的土地，我不认为他们会感到高兴。
比如说，印度给了你通过的权利。中国将全力以赴，向尼泊尔伸出援手。为什么？ 它希望保持尼泊尔作为一个中立的缓冲国，不希望在自己的后院再有一支军队。当你要对付一支愤怒的中国军队时，祝你好运。

Now, let's say China gives you march-by rights. Now India will play the savior. Agreed the Chinese army is superior, but, being nuclear, India does have sufficient deterrent. And besides, India, may rely on its old ally-Russia. After all, Russia as usual would like to get a foot in all the chaos too right?
Let's say you really play the diplomat and convince both India and China to stay out.
Now, after a 1000 mile March from the sea, from either India or China, your army finally reaches the borders of Nepal. And what do you see?
The mighty Himalayas.
Ever flown from Beijing or Shanghai to New Delhi? Even the planes don't fly over the Himalayas. They take a very circuitous route.
The trade between India and China stands at 76 billion dollars. Yet with all the mighty construction projects these countries have done, they couldn't make a highway through the Himalayas connecting one to the other.

现在，让我们假设中国给了你通过的权利。 现在，印度将扮演救世主的角色。虽然一致认为中国军队更优越，但是印度拥有核武器，确实有足够的威慑力量。 此外，印度可能会依赖它的老盟友俄罗斯。毕竟，俄罗斯像往常一样想插手混乱的局面，是吧？
让我们假设你真的扮演了外交官的角色，说服印度和中国都不参与进来。
现在，从印度或中国，经过1000英里的行军，你们的军队终于到达了尼泊尔的边界。 你看到了什么？雄伟的喜马拉雅山。即使是飞机也不能飞越喜马拉雅山。
印度和中国之间的贸易额为760亿美元。然而，尽管这些国家已经完成了如此庞大的建设项目，他们却无法修建一条穿越喜马拉雅山脉的高速公路，将两国连接起来。

Arnav Gautam Joshi , Indian by Birth, Indian by spirit.
Talking about the history, India has been invaded a numerous times. But now the scenario is a lot different. Now India is a unified nation just like USA ,earlier it was a land divided among various kings which continuously kept fighting with each other for land and power, most of the times India got invaded just because the kingdoms guarding its frontiers joined hands with the invading powers(Just like it happend in the case of Alexander's invasion).
But now we have the reputation of the fastest growing economy in the world ,Indian subcontinent now stands united with the 4th strongest army in the world.
Talking about Indian Defense Forces:
Total Indian Defense Force is even greater than China, Russia and USA(just double). I am not making facts below is the link.
List of countries by number of military and paramilitary personnel - Wikipedia, the free encyclopedia
List of countries by number of military and paramilitary personnel
Now let us talk about Indian Military Power in detail :
See it here: India Military Strength
Land Systems:
* Tanks: 6,464
* Armored Fighting Vehicles(AFV's): 6,704
* Self-Propelled Guns: 290
* Towed Artillery: 7,414
* Multiple-Launch Rocket Systems(MLVS): 292
Air Power:
* Total Aircraft: 2,0086
* Fighters/Interceptors: 679
* Fixed-Wing Attack Aircraft: 809
* Transport Aircraft: 857
* Trainer Aircraft: 318
* Helicopter: 646
* Attack helicopters: 19
Naval Power:
* Total Naval Strength: 295
* Aircraft Carriers: 2
* Frigates: 14
* Destroyers: 26
* Submarines: 14
* Coastal Defense Craft : 135
Standing Army:
Total Defense Forces: 4,768,407.(Beat that)
Active Frontline Personnel: 1,325,000
Active Reserve Personnel: 2,143,000
Para-military Forces: 2,288,407
Total Population: 1,251,695,584
Available Manpower: 616,000,000
Fit for Service: 489,600,000
Reaching Military age annually : 22,900,000
The reason why i am forcing on military power is that while invading a country:
* You will never use nukes on the country you want to invade or capture.
* While invading a country the main force you will encounter is its standing military strength.

Arnav Gautam Joshi 印度人
谈到历史，印度已经被侵略过无数次了。但现在情况大不相同了。 现在的印度和美国一样是一个统一的国家，早期的印度是一个分裂的国家，各国国王为了土地和权力不断地互相争斗，大多数时候，印度被入侵只是因为保卫其边界的王国与侵略者联手(就像亚历山大入侵时发生的情况一样)。
但是现在我们拥有世界上增长最快的经济体的名声，印度次大陆现在和世界上第四强大的军队团结在一起。印度的总防卫力量甚至比中国、俄罗斯和美国还要强(只是两倍)。现在让我们详细谈谈印度的军事实力。
陆地力量：
* 坦克: 6,464辆
* 装甲战车: 6,704辆
* 自行火炮: 290挺
* 拖曳炮兵: 7,414
* 多管发射火箭系统: 292
空中力量:
* 飞机总数: 2,0086架
* 战斗机 / 拦截机: 679架
* 固定翼攻击机: 809
* 运输机: 857
* 教练机: 318架
* 直升机: 646
* 攻击直升机: 19架
海军力量:
* 舰艇总数: 295艘
* 航空母舰: 2艘
* 护卫舰: 14艘
* 驱逐舰: 26架
* 潜艇: 14艘
* 海防船: 135艘
常备军:
国防部总兵力: 476.8万
在职前线人员: 132.5万
现役预备役人员: 214.3万
准军事力量: 228.8万
总人口: 12.5亿
可用人力: 6亿
适合服务: 4.89亿
每年达到军龄: 2.29亿
我之所以强调动用军事力量，是因为在入侵一个国家的时候:
* 你永远不会对你想入侵或占领的国家使用核武器。
* 入侵一个国家时，你会遇到的主要力量是它的常备军事力量。

* India is world's 2nd biggest population, any army who manages to defeat such a huge army will have lost its 3/4th strength already in the battle. Now the interesting thing is how will they manage the rebellion caused by a hostile population of 1,251,695,584 people. No chance of that to happen,no nation can control India for more than a few weeks.
Geographical Advantages Of Indian Sub-Continent:
Look at the geographical features of India
Also take the diversity of Indian Terrain this will tell you on how many terrains the Indian soilders are trained upon:
Kashmir( Below zero temperatures )
Thar( Above 50C temp.)
Forest:( You don't know from where your enemy can come from)
Water:
Now :
* Whole Northern and North-eastern border of India is covered with mountain ranges. It is an extremely difficult terrain. You can assume it as a thousand feet of naturally built wall for stopping you.

* 印度是世界上人口第二多的国家，任何一支能够打败如此庞大军队的军队都将在这场战斗中失去其三分之四的兵力。现在有趣的事情是他们将如何处理由12亿人的敌对人口引起的叛乱。这种情况不可能发生，没有一个国家能够控制印度超过几个星期。
印度次大陆的地理优势:
看看印度的地理特征
还有印度地形的多样性，这将告诉你印度士兵受训的地形有多少:
克什米尔(零度以下)
塔尔(温度超过50 °c)
森林: (你不知道你的敌人从哪里来)
* 整个印度北部和东北部边界被山脉所覆盖。这是一个极其困难的地形。你可以假设它是一千英尺的自然形成的墙阻止着你。

* On the western border we have extremely hot,vast and treacherous Runn of Kuchh and Thar Desert. You don't know what is lying in the sand.
* The only venerable side of Indian geography is its southern border where it is covered by ocean from three sides. For which India has a quiet capable navy,missile technology, nuclear submarines and what not you just need to name it.
Thus India is like a natural fort situated at river bank.
Now what you have to do:
(1) First get through the natural fortification of India facing One of the fiercest border defense forces of the world.
(2)Then you need to fight all the defense forces whose strength may be greater than the population of your country.
(3) Then you need to control the rebellions caused by a population of 1,251,695,584 people.
(4) Last thing you need to do is to survive your escape.
QUIET EASY RIGHT!!
Real World Scenario:
(1) USA will not dare to invade India, because Russia will never tolerate any further US expansion on Asian Soil.
(2) Russia will not dare to invade India, because America will never tolerate any further Russian expansion on Asian soil.
(3) China will not dare to invade India because no country in this world will like to see China expand.
These three countries have so called stronger military than India and when they cannot Invade us then no one else can.
Also we are a peaceful and defensive country (Not an aggressor or invader bully like america) so there are less chances that we get involved in a war.

* 在西部边境，我们有极其炎热、广阔和危险的库奇和塔尔沙漠。你不知道沙滩上有着什么。
* 印度唯一令人尊敬的一面是其南部边界，那里从三面环海。 印度拥有实力雄厚的海军、导弹技术、核潜艇和其他你能说出来的东西。因此，印度就像一个位于河岸的天然堡垒。
现在你要做的是：
(1)面对世界上最猛烈的边防部队，首先穿过印度的自然防御工事。
(2)然后你需要与所有的国防部队作战，这些部队的兵力可能比你们国家的人口还多。
(3)然后你需要控制由12.5亿人口引起的叛乱。
(4)你最不需要做的事情就是逃生。
返回现实世界:
(1)美国不敢入侵印度，因为俄罗斯绝不会容忍美国在亚洲领土上的进一步扩张。
(2)俄罗斯不敢入侵印度，因为美国绝不会容忍俄罗斯在亚洲领土上进一步扩张。
(3)中国不敢入侵印度，因为世界上没有一个国家愿意看到中国扩张。
这三个国家拥有所谓的比印度更强大的军事力量，但当他们不能侵略我们的时候，别人也不能。
而且我们是一个和平的防御性国家(不像美国那样是侵略者) ，所以我们卷入战争的可能性更小。

Jaime Garrigues , studied Physics and Chemistry & History of World at Nuestra Señora Santa Maria
1.The US:
The US is the most difficult country to invade due to its geography. The US is far away from any other continent and is separated from them by water, and only shares 2 common borders with Canada and Mexico ( which aren't a threat to the US and they both are allies to the US), so the only way to invade the US without the intervention of Mexico or Canada is water, so holding an invasion and a supplying line from:
- Pekin to California: 9753km (China)
-Kaliningrad to Portland: 8336km or Kamchakta to Oregon: 5536km (Russia)
Holding this support line will be very difficult because of the trip, but if they manage to surpass the US Navy and US Air Force, they will have to manage a great variety of terrain such as deserts, jungles, ice deserts (Alaska), huge mountains on the west, and very tough people. If this isn't enough, all NATO, MNNA countries and other allied countries will go and help the US with anything they can contribute to.
2.Russia:

Jaime Garrigues ，攻读物理、化学及世界史
1. 美国:
由于其地理位置，美国是最难入侵的国家。 美国与其他大陆相距遥远，与它们之间隔着海洋，与加拿大和墨西哥只有两条共同边界(这两条边界对美国不构成威胁，而且它们都是美国的盟友) ，因此，在没有墨西哥或加拿大干预的情况下入侵美国的唯一途径就是走海洋，因此拥有入侵和补给线的国家有:
北京到加州: 9753公里(中国)
加里宁格勒到波特兰: 8336公里，或者堪察加半岛到俄勒冈州: 5536公里
由于这次行军，保持这条支援线将非常困难，但如果他们设法跨过美国海军和空军，他们将不得不面对各种各样的地形，如沙漠、丛林、冰沙(阿拉斯加)、西部的巨大山脉和非常坚韧的人民。如果这还不够的话，所有北约、 主要非北约盟友国家和其他盟国都会去帮助美国，尽他们所能。

Everyone knows the saying: “Never invade Russia in winter”. Many powerful countries have TRIED to invade Russia but failed in the attempt, ask Hitler or Napoleon. Russia is located between two continents Asia and Europe, and separated from the US by the Bering Straight, and it is 17 million square kilometres, the largest country in the world and with about 145 million inhabitants. Let's say someone wants to invade from west, they will have to face with a mountainous landscape, difficult to transport troops and vehicles, then will have to go through the Ural Mountains which by then, will be very fortified and it has a difficult access. The main problem for Russia is that it has common border with a lot of countries which will hinder Russian defense lines.
3. Afghanistan:
Afghanistan has a mountainous terrain in most of the country which would difficult any invasion, and this mountains can be perfect for traps and ambushes against the enemy. Afghanistan geography also has deserts with no shapes to protect from sun, no water no nothing. History has teached us that Afghanistan is where most empires have fall.
4. China:

2. 俄罗斯:
人人都知道这句谚语：“永远不要在冬天入侵俄罗斯”。 许多强国都曾试图入侵俄罗斯，但都以失败告终，不信可以问问希特勒或拿破仑。俄罗斯位于亚洲和欧洲两大洲之间，与美国之间隔着白令海峡，面积1700万平方公里，是世界上最大的国家，约有1.45亿居民。 假设有人想从西面入侵，他们将不得不面对山区，难以运送部队和车辆，然后将不得不经过乌拉尔山脉，但是难以进入。俄罗斯的主要问题是，它与许多国家有共同的边界，使它很难被入侵。
3. 阿富汗:
阿富汗大部分地区都是多山地带，入侵很困难，这些山脉是陷阱和伏击敌人的绝佳地点。 阿富汗的地理位置也有沙漠，没有躲避可以遮挡阳光照射，没有水，什么都没有。历史告诉我们，阿富汗是大多数帝国陨落的地方。

China, the 4th largest country in the world will be difficult to invade due to its size and its mountains. China has the highest mountainous chain as a natural barrier in the world, the Tibet and the Himalaya a 2400km barrier which to encompas it will last a lot (even with planes will be difficult as visibility over there isn't good) and will slow and even stop any invasion through there. But it doesn't end there, invadors will have to go through the Gobi desert, and a lot of rivers and deep forests as well.
5. Iran:
Iran is a large country with a lot of natural barriers such as the Zagros mountains, the Alborz mountains and the Great Salt Desert which will complicate resupplying (mainly water).
6. Vietnam:
Not even the US could take it because of its deep forests and jungles.
7. Switzerland:

4. 中国：
中国是世界上第四大国家，由于它的面积和山脉，很难被入侵。 中国拥有世界上最高的山脉链作为天然屏障，西藏和喜马拉雅有一个2400公里的屏障，将会延长很长时间(即使有飞机也很难飞越，因为那里的能见度不好) ，并将减缓甚至阻止任何通过那里的入侵。 但是它并不止于此，侵略者将不得不穿越戈壁沙漠，以及许多河流和深林。
5. 伊朗:
伊朗是一个大国，有许多天然屏障，如札格罗斯山脉、 阿尔博兹山脉和大盐沙漠，这将使补给(主要是水)复杂化。
6. 越南:
即使是美国也无法承受，因为它拥有深邃的森林和丛林。

This tiny but bully country will make suffer your troops and vehicles while trying to trespassing the Alps and its multiple bunkers. Even Hitler feared the defeat over this country.
8. Canada:
The second largest country on the world mainly made of an icy desert, it has one mountainous chain, the Rocky Mountains, but because of the ice desert and because it has 36563 islands which will make Canada difficult to conquer.

7. 瑞士:
这个弹丸之地的国家会让你的军队和车辆在试图越过阿尔卑斯山脉和多个掩体时受苦。就连希特勒也害怕在这个国家的战败。
8. 加拿大:
作为世界上第二大的国家，加拿大主要是由冰雪覆盖的沙漠组成的，它有一条山脉---- 落基山脉，但是由于冰雪覆盖的沙漠和36563个岛屿，加拿大很难被征服。

Zakaria Islam , Student of International Relations
Top 3 countries - the most difficult to invade:
1. United States: The whole territory of USA is isolated by the Pacific in the west, by the Atlantic in the east and south and the cold Canada covers the north. The situation is, you cannot just invade USA flying from the mainland Africa, Asia or even Europe and USA would not let you to set up any military bases near the Americas (north/south).
2. Canada: The same conditions are applicable for Canada. Moreover, the geographic location and the weather condition of it remains a matter of tension for the others.
3. Russia: Others can invade Russia but the affected area would surely be very small and very easy to regain for Russia. History shows the downfalls of the invasions towards Russia such as Napoleon's invasion of Russia in 1812 and Hitler's during the WWII. So, the size and geography of Russia will make the difference.

Zakaria Islam ，国际关系学生
最难入侵的3个国家：
1. 美国: 美国的全部领土都被西部的太平洋隔离开来，而东部和南部被大西洋隔离，北部被寒冷的加拿大所覆盖。情况是，你不能从非洲大陆、亚洲甚至欧洲直接入侵美国，美国不允许你在美洲(南北)附近建立任何军事基地。
2. 加拿大: 同样的条件也适用于加拿大。此外，它的地理位置和天气状况对其他国家来说仍然是一个棘手的问题。
3. 俄罗斯: 其他国家可以入侵俄罗斯，但受影响的地区肯定很小，俄罗斯很容易就能夺回。历史已经显示了侵略俄国所导致的失败，例如1812年拿破仑入侵俄国和二战期间希特勒入侵俄国。 因此，俄罗斯的面积和地理位置将会对入侵产生不利影响。

Hari Sanil , Geography expert
I would go with either Canada or Russia.Canada is protected to the east and west by huge oceans that prevent European or Asian superpowers from attacking. Their navies would be bashed up in the rough ocean and by the time they get to Canada, they have to sail through many islands (as Jon had earlier stated).To the north, it is locked by the Arctic, which would be impossible to cross. Even if you got through the ice, pretty much all of the population is in the south, meaning you'd have to march another few hundred miles with an aldready exhausted military. So what of the south? Eternally guarded by the United States, who is Canada's best friend.Now for Russia. Like Canada, the population is concentrated in one general region, the European (west) side. On the European side, there are no countries that could invade it except France or Germany, both of whom have tried in the past but failed miserably.On the east, there is China and the United States. The US is out of the question here, since they would have to get through thousands of miles of Siberia and they would all freeze to death long before reaching the West. China would also suffer a similar fate, although they have a larger army so they might be able to get a little farther. But wait, there's the Ural Mountains. They will block out any intrusion from the east.

Hari Sanil 、地理专家
我会选择加拿大或俄罗斯。加拿大东部和西部被巨大的海洋保护着，这些海洋阻止了欧洲或亚洲超级大国的进攻。他们的海军将在波涛汹涌的海洋中遭受重创，当他们到达加拿大时，他们不得不穿越许多岛屿。在北部，北极圈围绕着加拿大，所以是不可能穿越的。即使你穿过了冰层，几乎所有的人口都在南方，这意味着你不得不带着疲惫不堪的军队再行军几百英里。那么南方呢？ 美国是加拿大最好的朋友，它永远守护着这个国家。
现在轮到俄罗斯了。 像加拿大一样，人口集中在一个大的地区——欧洲(西部)。在欧洲部分，除了法国和德国之外，没有其他国家可以入侵它，这两个国家过去都曾尝试过，但都以惨败告终。 美国也是不可能的，因为他们必须穿过数千英里的西伯利亚，而且他们在到达之前都会被冻死。 中国也将遭受类似的命运，尽管他们有一支规模更大的军队，所以他们可能会走得更远一点。 但是，等等，还有乌拉尔山脉。他们将阻挡来自东方的任何入侵。

Amit Meltzer , Old guy from Israel, curious about many things.
I;m so tired of the old successful myth about the impregnable Swiss Alps fortress. Look at the map fellows, Switzerland is not surrounded by the Alps, her entire resources (except skiing resorts) are down in hilly country or near rivers. Any European army could take over Switzerland in several weeks.
History shows us that the most difficult countries to conquer in the world are Russia and Afghanistan, followed by China, Ethiopia and Algeria.
the reasons have everything to do with terrain, one of the key parameters of strategic design. These countries are either too big or too mountainous to conquer and hold.
- Russia defeated every conquering army that invaded her except the Mongols, and arguably the several princely states in the 13th century weren't a cohesive nation or country as we perceive it today. - Afghanistan defeated attempts to conquer and hold by the British, Soviets and Americans, and Alexander the Great had to resort to near genocide slaughter to semi-break them. The Afghans even successfully invaded India and occupied Delhi a while back.

Amit Meltzer 来自以色列的老家伙，对很多事情都很好奇。
我已经厌倦了关于瑞士坚不可摧的阿尔卑斯山要塞的古老神话。伙计们，看看地图，瑞士并不是被阿尔卑斯山包围，她的所有资源(除了滑雪场)都在山地或河流附近。任何一支欧洲军队都可以在几周内占领瑞士。
历史告诉我们，世界上最难征服的国家是俄罗斯和阿富汗，其次是中国、埃塞俄比亚和阿尔及利亚。原因与地形有关，地形是战略设计的关键参数之一。 这些国家要么太大，要么太多山，难以征服和占领。
俄罗斯击败了除了蒙古人以外的所有入侵俄罗斯的军队，可以说13世纪的几个王国并不是我们今天看到的一个有凝聚力的民族或国家。
阿富汗击败了英国、苏联和粉碎了美国试图征服和占领阿富汗的企图，亚历山大大帝不得不采取近乎灭绝种族的屠杀手段来半粉碎他们。阿富汗人甚至成功地入侵了印度，并在不久就占领了德里。

China also proved highly resistant to total conquest, only succumbing twice to outside usurpers in several thousand tumultuous years of warfare. And you can ask France how tenuous was her hold on Algeria away from the coastal strip.
The most difficult countries to conquer are those that can sap the invader's resources and will to fight by a combination of bad terrain and will to fight. Those are the countries to veer away from if you value your resources or your reputation.

事实证明，中国对全面征服具有高度抵抗力，在几千年动荡的战争中，只有两次屈服于外来篡夺者。你可以问问法国，她对远离海岸线的阿尔及利亚的控制是多么的脆弱。
最难征服的国家是那些能够耗尽入侵者资源，并且通过恶劣地形和战斗意志的组合来战斗的国家。 如果你珍惜你的资源或者你的声誉，那么这些国家就是你应该避免侵略的地方。

Jon Davis , Can find any country on Google Maps with labels turned off.
I want to say Canada. The first notable reasons are these two huge oceans which basically prevents everyone in North America from concerning themselves with the threat of international invasion. Second, the entire western portion is covered with high and inhospitable mountain ranges with lower level mountains encumbering an eastern invasion. The only real way to bypass this is to sail through a gauntlet of islands and narrow straights to invade through the Hudson bay or Great Lakes. To do that would be a really dangerous operation almost surely doomed to defense forces. The only best third option would be to literally walk over the North Pole, which, being that it is a frozen ocean, would be one of the most impressive logistical feats in history, followed only by one of the most difficult fought wars ever, since it would have to take place during the winter. Follow this with the fact that most the country is composed of woodlands and inhospitable tundra you have a recipe for insurgent activity that could last for years from those who know the territory well. I know that many would argue about that Southern border, but realistically speaking, the US and Canada have had a bromance going on for generations. Seriously, I've heard that it is the longest running uncontested border in history. While its existence somewhat seems to ignore the intent of the OP, we might as well say that there is an invisible wall protecting Canada's Southern Border in the form of millions of armed American service people and hundreds of millions of Americans themselves.

Jon Davis ，可以在谷歌地图上找到任何关闭标签的国家
我想说加拿大。第一个值得注意的原因是周围有两个巨大的海洋，它们基本上阻止了北美洲的入侵威胁。其次，整个西部地区覆盖着高耸而荒凉的山脉，阻碍着东部的侵略。唯一真正管用的办法是，绕过岛屿和狭窄的直道，通过哈德逊湾或五大湖入侵。这样做将是非常危险的行动，几乎肯定的是要失败的。唯一最好的第三选择就是穿越北极，因为它是一片冰冻的海洋，这将是历史上最令人印象深刻的后勤壮举之一，紧随其后的是一场有史以来最艰难的战争，因为它必须在冬天来临之前。接下来的事实是，这个国家大部分是由林地和荒凉的苔原组成的，你会面临叛乱的活，可以持续多年，并且这些人对这片土地非常了解。我知道很多人会为南部边界争论不休，但是实事求是地说，美国和加拿大的兄弟情已经持续了好几代。说真的，我听说这是历史上最长的无争议边界。虽然它的存在似乎有点忽视了执行任务的意图，但我们不妨说，有一堵无形的墙保护着加拿大南部边境，那里是数百万美国武装军人和数亿美国人。

Shumem Abdullah
Afghanistan is known as the "Imperial Cemetery".
Afghanistan is a landlocked country, located in the heart of Asia.
From ancient times to now, from the great Alexander to Genghis Khan, from the British Empire to the United States. Afghanistan has experienced the invasion of almost all major powers in history, but never been conquered. The most typical representative is the Red Soviet Empire.
Afghanistan is often referred to as the crossroads of Central Asia, and its history is full of war and social unrest. Historically, the area now known as Afghanistan is at the edge of many major empires in various periods, mainly the Persian empire, the peacock dynasty, Kushan Empire, the Tang dynasty, the Qing dynasty, the British Empire and the Soviet Union, and the other including Genghis Khan and Alexander the Great The establi Empire.

Shumem Abdullah
阿富汗被称为“帝国坟场”。
阿富汗是位于亚洲中心的内陆国家。
从古代到现在，从伟大的亚历山大到成吉思汗，从大英帝国到美国 历史上几乎所有的大国都曾入侵过阿富汗，但从未被征服过。最典型的代表是红色苏维埃帝国。
阿富汗通常被认为是中亚的十字路口，它的历史充满了战争和社会动荡。历史上，现在被称为阿富汗的地区，在不同时期处于许多主要帝国的边缘，主要是波斯帝国、孔雀王朝、 贵霜帝国、唐朝、清朝、大英帝国和苏联，以及其他包括成吉思汗和亚历山大大帝建立的帝国。

Since 1900, 11 leaders have not completed their tenure due to non-democratic events: 1919 (assassination), 1929 (resignation), 1929 (put to death), 1933 (assassination), 1973 (replace), 1978 ( put to death), 1979 (put to death), 1979 (put to death), 1987 (depose), 1992 (overturned), 1996 (overturned) and 2001 (overturned).
In 1979, the Soviet invasion of Afghanistan had intended to end the war within three months, but in fact it lasted for ten years.
100000 Soviet troops did not defeat the Afghan jihadists, so some people say that Afghanistan is "the Vietnam of Soviet Union ".
As a result of the resistance of the anti-Soviet jihad guerrillas, in 1989, the Soviet Union withdrew from Afghanistan. In 1992 the Soviet Union fostered the Muhammad Najibullah regime completely collapsed, and Afghanistan is still divided until now. Jihad warriors have been fighting between different factions, leading to the division of warlords, internal conflicts caused many factions. The most serious conflict occurred in Kabul in 1994, where about 10,000 people were killed in sectarian clashes.

自1900年以来，共有11位领导人因非民主事件未能完成任期: 1919年(暗杀)、1929年(辞职)、1929年(处死)、1933年(暗杀)、1973年(替换)、1978年(处死)、1979年(处死)、1979年(处死)、1987年(废黜)、1992年(推翻)、1996年(推翻)和2001年(推翻)。
1979年，苏联入侵阿富汗，本打算在三个月内结束战争，但事实上战争持续了十年。
10万名苏联士兵没有击败阿富汗的圣战分子，所以一些人说阿富汗是“苏联的越南”。
由于反苏圣战游击队的抵抗，苏联于1989年从阿富汗撤军。1992年，苏联扶植的穆罕默德 · 纳吉布拉政权彻底崩溃，阿富汗至今仍处于分裂状态。圣战战士一直在不同派别之间作战，导致军阀分裂，内部冲突造成许多派别。 最严重的冲突发生在1994年的喀布尔，当时约有1万人在教派冲突中丧生。

Afghanistan has more than 20 ethnic groups, each ethnic group has its own language. But because of the complex terrain, they rarely communicate with each other. Many countries that have invaded Afghanistan have failed because of insufficient logistics supplies.
In 2001, the United States air strikes Afghanistan, from 2001 to 2014.
Afghanistan is a mountainous country.
So it is difficult for Afghanistan to be completely conquered.
Now the Afghan women:
Extreme religion is terrible.

阿富汗有20多个民族，每个民族都有自己的语言。 但是由于地形复杂，他们很少相互交流。 许多入侵阿富汗的国家由于后勤供应不足而失败。
2001年，美国空袭了阿富汗，从2001年到2014年。
阿富汗是一个多山的国家。
所以阿富汗很难被彻底征服。