Nahanni National Park might very well be the greatest national park in the world. That is a big statement, but anyone who has been to Nahanni (and few people have) can back it up.

Nahanni is home to one of the world's largest waterfalls (Virginia Falls) which is higher than Niagara Falls and has a flow comparable with Victoria Falls in Africa.

That alone would be enough to make it a world heritage sites. However, it is also home to the Cirque du Unclimables, which is a stunning collection of mountain peaks, and the Ram Canyon, which is one of the most impressive canyons in the world. 

Nahanni only gets about 800 visitors per year. There are no roads to the park, so the only way to enter is by hiking or float plane. There is also a very short season of about 2 months where visitors can enter.