The longest cave in the world is the 'Mammoth Cave System' in the USA at 560,000 mtrs deep!
63
10 of the tributaries flowing into the Amazon river are as big as the Mississippi river.
41
The state with the longest coastline in the Continental U.S. is Michigan.
31
Due to gravitational effects, you weigh slightly less when the moon is directly overhead.
55
Europe is the only continent without a desert.
62
The Niagara Falls moves upstream at an average rate of about 295ft a century!
48
It takes a drop of ocean water more than 1,000 years to circulate around the world.
61
The North Atlantic gets 2.5 centimetres (1in) wider every year.
119