Venice Island was built on a foundation of tree trunks. 1200 years later, those same trunks still support almost all of central Venice.
8
The Caspian Sea is also classed as the world's largest lake.
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Due to gravitational effects, you weigh slightly less when the moon is directly overhead.
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Australia's Great Barrier Reef is 1,250 miles long!
45
The Sahara desert expands at about 1km per month.
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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.
17
It takes a drop of ocean water more than 1,000 years to circulate around the world.
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