The longest cave in the world is the 'Mammoth Cave System' in the USA at 560,000 mtrs deep!
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The city of Houston, Texas is built on a swamp and is slowly sinking!
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The state of Florida is bigger than England!
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The Amazon rainforest produces more than 20% the world's oxygen supply.
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The Sahara desert expands at about 1km per month.
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Louisiana is the only state that grows in land area every year (Due to alluvial deposits from the Mississippi River).
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The Caspian Sea is also classed as the world's largest lake.
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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.
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