Christmas Island has bridges for crabs to stop them getting run over during the mass migration.
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In 1916, a US amendment was proposed to put all acts of war to a national vote. If you voted yes you would have to register as a volunteer for service in the United States Army.
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Leonardo Da Vinci made a robotic lion in 1515 that would walk, sway, open its mouth and move its tail - it even had a compartment that opened to present flowers.
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In 1999, Harvard physicist Lene Hau was able to slow down light to 17 meters per second and in 2001, was able to stop light completely.
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