10 of the tributaries flowing into the Amazon river are as big as the Mississippi river.
41
An earthquake on Dec. 16, 1811 caused parts of the Mississippi River to flow backwards.
243
It's still possible to see the division between East and West Germany due to different light bulbs.
5
There's a lake under Antarctica that is 25 million years old called Lake Vostok.
109
More than a dozen men have stood on the surface of the moon, but only three have been to Challenger Deep in the Marianas Trench, the deepest known spot in the ocean.
17