The longest cave in the world is the 'Mammoth Cave System' in the USA at 560,000 mtrs deep!
63
A volcano has enough power to shoot ash as high as 50 km into the atmosphere.
59
10 of the tributaries flowing into the Amazon river are as big as the Mississippi river.
41
The average ice berg weighs 20,000,000 tons!
54
Australia's Great Barrier Reef is 1,250 miles long!
45
More than 25% of the world's forests are in Siberia.
51
One cubic mile of seawater contains about 50 pounds of gold.
79