An earthquake on Dec. 16, 1811 caused parts of the Mississippi River to flow backwards.
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Even Antarctica has an area code. It's 672.
58
One cubic mile of seawater contains about 50 pounds of gold.
79
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
Connecticut and Rhode Island never ratified the 18th Amendment (Prohibition).
25
The state with the longest coastline in the Continental U.S. is Michigan.
31