The longest cave in the world is the 'Mammoth Cave System' in the USA at 560,000 mtrs deep!
63
The Amazon rainforest produces more than 20% the world's oxygen supply.
182
It takes a drop of ocean water more than 1,000 years to circulate around the world.
61
Every year, Alaska has about 5,000 earthquakes.
31
Even Antarctica has an area code. It's 672.
58
Check your map! The Pacific entrance of the Panama Canal is farther East than the Atlantic entrance.
40
Forest fires move faster uphill than downhill.
52
Venice Island was built on a foundation of tree trunks. 1200 years later, those same trunks still support almost all of central Venice.
8