The Caspian Sea is also classed as the world's largest lake.
52
The state with the longest coastline in the Continental U.S. is Michigan.
31
There's a lake under Antarctica that is 25 million years old called Lake Vostok.
109
The city of Houston, Texas is built on a swamp and is slowly sinking!
89
A volcano has enough power to shoot ash as high as 50 km into the atmosphere.
59
The Amazon rainforest produces more than 20% the world's oxygen supply.
182
An earthquake on Dec. 16, 1811 caused parts of the Mississippi River to flow backwards.
243
10 of the tributaries flowing into the Amazon river are as big as the Mississippi river.
41