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
One cubic mile of seawater contains about 50 pounds of gold.
79
There's a lake under Antarctica that is 25 million years old called Lake Vostok.
109
10 of the tributaries flowing into the Amazon river are as big as the Mississippi river.
41
A waterfall known as The Devil's Kettle empties water into a hole and nobody knows where it ends up!
18