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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Israel's Dead Sea is 1,312 feet below sea level.
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More than 25% of the world's forests are in Siberia.
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10 of the tributaries flowing into the Amazon river are as big as the Mississippi river.
41
The city of Houston, Texas is built on a swamp and is slowly sinking!
89
The Sahara desert expands at about 1km per month.
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The longest cave in the world is the 'Mammoth Cave System' in the USA at 560,000 mtrs deep!
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The Caspian Sea is also classed as the world's largest lake.
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