An earthquake on Dec. 16, 1811 caused parts of the Mississippi River to flow backwards.
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Due to gravitational effects, you weigh slightly less when the moon is directly overhead.
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One cubic mile of seawater contains about 50 pounds of gold.
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In 1850, only 8% of the people in California were women.
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The Amazon rainforest produces more than 20% the world's oxygen supply.
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Australia's Great Barrier Reef is 1,250 miles long!
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