Venice Island was built on a foundation of tree trunks. 1200 years later, those same trunks still support almost all of central Venice.
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Mexico City is built on top of an underground resevoir!
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The Niagara Falls moves upstream at an average rate of about 295ft a century!
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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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A volcano has enough power to shoot ash as high as 50 km into the atmosphere.
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Every year, Alaska has about 5,000 earthquakes.
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