10 of the tributaries flowing into the Amazon river are as big as the Mississippi river.
41
Mexico City is built on top of an underground resevoir!
47
It takes a drop of ocean water more than 1,000 years to circulate around the world.
61
The longest cave in the world is the 'Mammoth Cave System' in the USA at 560,000 mtrs deep!
63
There are more than 50,000 earthquakes throughout the world every year!
47
Australia's Great Barrier Reef is 1,250 miles long!
45
The city of Houston, Texas is built on a swamp and is slowly sinking!
89