Scientists lit a cave of natural gas on fire in 1971 expecting it to only burn for a few days; it still burns to this day. It has been nicknamed "The Door to Hell".
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There are pictures of Knights fighting Snails in old Medieval manuscripts - and nobody knows why.
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There's a mysterious dwarf planet between Mars and Jupiter called 'Ceres' which has never been visited by spacecraft or photographed in detail, however, Earth-bound telescopes reveal a large bright shining spot on the surface of this planet, the origin and nature of which are unknown.
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In 1518, a "dancing plague" struck Strasbourg, Alsace, whereby hundreds of people danced fervently in the streets over the period of a month. Some suffered heart attacks or strokes, and many others died from sheer exhaustion. It remains unexplained.
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In 1968, a car driven by bank employees was pulled over by a motorcycle cop claiming the car had been rigged with a bomb. The cop got under the car to “defuse” the device. When the car started to smoke, everybody ran. Then the “cop” just drove the car away. The 300,000,000 Yen robbery remains unsolved to this day.
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