The longest cave in the world is the 'Mammoth Cave System' in the USA at 560,000 mtrs deep!
63
If Manhattan had the same population density as Alaska, there would only be 15 people living there.
138
It takes a drop of ocean water more than 1,000 years to circulate around the world.
61
Forest fires move faster uphill than downhill.
52
There are approximately three chickens for every human on Earth.
13
If Antarctica's ice sheets melted, the worlds oceans would rise by 60 to 65 metres (200 - 210ft) - everywhere
181
Mexico City is built on top of an underground resevoir!
47
Israel's Dead Sea is 1,312 feet below sea level.
48