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
10 of the tributaries flowing into the Amazon river are as big as the Mississippi river.
41
Forest fires move faster uphill than downhill.
52
The Amazon rainforest produces more than 20% the world's oxygen supply.
182
There are approximately three chickens for every human on Earth.
13
In 1850, only 8% of the people in California were women.
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