A waterfall known as The Devil's Kettle empties water into a hole and nobody knows where it ends up!
18
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
Australia's Great Barrier Reef is 1,250 miles long!
45
The average ice berg weighs 20,000,000 tons!
54
An earthquake on Dec. 16, 1811 caused parts of the Mississippi River to flow backwards.
243
The city of Houston, Texas is built on a swamp and is slowly sinking!
89
The warmest temperature ever recorded on Antarctica was 3 degrees F.
175