The Amazon rainforest produces more than 20% the world's oxygen supply.
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More than a dozen men have stood on the surface of the moon, but only three have been to Challenger Deep in the Marianas Trench, the deepest known spot in the ocean.
17
Every year, Alaska has about 5,000 earthquakes.
31
The Niagara Falls moves upstream at an average rate of about 295ft a century!
48
10 of the tributaries flowing into the Amazon river are as big as the Mississippi river.
41
Israel's Dead Sea is 1,312 feet below sea level.
48
Check your map! Virginia extends farther west than West Virginia.
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