The Sahara desert expands at about 1km per month.
90
The Atlantic Ocean is saltier than the Pacific Ocean.
54
Australia's Great Barrier Reef is 1,250 miles long!
45
Mexico City is built on top of an underground resevoir!
47
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
One cubic mile of seawater contains about 50 pounds of gold.
79