The longest cave in the world is the 'Mammoth Cave System' in the USA at 560,000 mtrs deep!
63
The Atlantic Ocean is saltier than the Pacific Ocean.
54
Australia's Great Barrier Reef is 1,250 miles long!
45
The state with the longest coastline in the Continental U.S. is Michigan.
31
The city of Houston, Texas is built on a swamp and is slowly sinking!
89
There's a lake under Antarctica that is 25 million years old called Lake Vostok.
109
The state of Florida is bigger than England!
74