Top 10 Hardest Countries to Conquer

The United States of America is often the subject of ridicule from other developed nations. Take Pink Guy's "White Is Right", or Europeans and Australians criticizing the US Government for its controversial lack of gun control.
But when there is a crazy dictator, or another country is about to get conquered, the US Army comes in. A lot of the US taxpayers' money winds up in this country's military.
The US also has the first National Park in the world. In total, they have more than 400, each one vastly different from the other. With a land area, also comes geographical diversity, which is often annoying for invaders.
With people power, land area, and more gun power than people power, the USA really fits perfectly for a list like this.

Some countries like Australia have a lot of land area, but not so many inhabitants. Others like Bangladesh lack land area, but they have the people power. China is one country that has both. They have more than 10 percent of the world's population, and are the 4th largest in physical area. Furthermore, with one of the largest economies in the world and industrial prowess, China is not an easy target.

Tibet is the main reason China is hard to invade, but even without Tibet, China is no easy target. This is mostly due to how strong China's millitary is, and how large China's economy is.

One of Napoleon's and Hitler's biggest mistakes were to try taking over Russia. Russia is currently the biggest country in the world (by land area), and they have a ton of petroleum power like Saudi Arabia. Even if you try to go for Russia during summer, the Russians can hold off and easily fight back during winter, when the temperatures are around -20 degrees Celsius, which only the Russians are prepared for.

Napoleon and Hitler shouldn't have tried taking over Russia, and they are the largest country in the world. Oh, and Siberia, especially in winter. But even if you try going for Russia in summer, or even spring, Russia's strong military can still hold till winter, when the temperatures are about -20 degrees Celsius.

Another one of these big countries is Canada, but they have another defense on them. Canada is surrounded by ocean, but the safest way to get at Canada is through the southern parts of the coast. However, Canada is friends with the United States, and the USA is known for its strong military and they often intervene in international conflicts. Canada, like North Korea is essentially like facing two countries instead of one.

Canada is the 2nd largest country, and with the USA allied with them, it is not going to be easy to invade them. What makes Canada even harder to invade is that their Northern part is basically a North American Siberia.

Australia is known for cities like Sydney, but only its coast is well populated and taken into consideration. Australia has an desert called the Outback in the middle of the continent, which will be very challenging for enemy armies. Furthermore, Australia is hard to get to, and will need a bigger army than navy to take over the Outback, and don't try cramming everything on to your naval ships.

Unless you want to deal with an additional army of spiders, kangaroos and emus, don't invade Australia. They also have a strong army just in case the emus, kangaroos and spiders don't do the trick.

This one is not quite as obvious as some of the other countries on the list, but it's pretty much Afghanistan in the west, and Brazil in the east. India is a physically diverse nation, with many different environments, and a dense and population, which means it has a big military. And don't try taking the south of India because the coast is always full of submarines.

The only really easy way to invade a civilization in India is to do it by sea. You can't really use paratroopers, unless you drop them from a helicopter, and invading it by land is no small feat due to it basically being Arizona on the west, and Brazil on the east. And doing it by sea now is nearly impossible due to submarines.

Many empires have tried to conquer Afghanistan, but hardly anyone succeeded. Afghanistan is a desert surrounded by the Hindu Kush, and the US is having a hard time there. Almost every empire that tries their armies against Afghanistan end up losing. This gives Afghanistan a potential nickname of "the graveyard of empires".

You know, for a country known for parades every spring and thick, dense jungles... Yeah, good luck with the Amazon Rainforest. It is hard to navigate, and has a ton of dangerous, toxic predators that most armies are not prepared for. And because it's a mostly a RAINforest, armies are easy targets to get flooded out.

Invading an island is hard enough due to little supply, let alone when that island was one of the oldest civilizations and still hasn't been invaded. Heck, even the Mongols couldn't invade Japan, and all the Mongols really did was invade countries.
And now it's even harder to invade Japan due to how good their military is.

If you ever try to fight North Korea, Kim Jong Un would literally bomb you with missiles

Denmark looks like an easy target on the map. And I wouldn't blame you. However, Denmark controls Greenland, more than 1,000,000 square kilometers of almost no resources, and it is very hard to survive in due to its cold temperatures. Denmark better not sell it off to the United States of America, or it will lose its place on our list

Like Switzerland, they are also safe from invasion as it's pointless to conquer them

If you're surrounded by people who don't want you to exist, it's obvious that you must be tough as possible. Not only is their army powerful in the first place, but they also have protection from the USA, so invading them is no small feat.

They should be higher, considering you have to go through the States to even get to attempt your first move, in which you would fail utterly.

They never be defeated by US, China and Japan, France.

They're backed up by India, Russia, and China, so you'll have to fight them to fight Sri Lanka