The Mekong River passes through six countries and supports 60 million people who depend on it for food.

The Amazon rainforest produces about 20% of the world's oxygen.

The Roman navy played a key role in Mediterranean dominance.

The Aztec capital Tenochtitlan had a population of around 200,000 in the early 16th century, larger than most European cities.

Canada has more lakes than every other country combined.

There is a town in Norway called Hell — it regularly freezes over in winter.

The Millau Viaduct in France is one of the tallest bridges in the world.

More people live in Tokyo than in the entire country of Canada.

The Andes Mountains are still rising today.