An earthquake on Dec. 16, 1811 caused parts of the Mississippi River to flow backwards.
243
Venice Island was built on a foundation of tree trunks. 1200 years later, those same trunks still support almost all of central Venice.
8
It takes a drop of ocean water more than 1,000 years to circulate around the world.
61
If Manhattan had the same population density as Alaska, there would only be 15 people living there.
138
The longest cave in the world is the 'Mammoth Cave System' in the USA at 560,000 mtrs deep!
63
Every person in the world can fit in Texas and be given over 1000 sq ft in which to live.
14