They actually built the Pyramids by starting and finishing from the "inside" of them..17degree upward slopes were built to keep dragging up each 6 ton piece of rock right up to the top
4 members of the mafia were responsible for the death of Kennedy (one of them missed him), they were hired by the FBI and the CIA
Stonehenge was a religious artifact built by the ancient druids..When the Romans came along and made an encampment they saw how they sacrificed people and so they started pulling it down, but a message from one of their couriers said that they were needed very quickly and they turned their attention to packing up the encampment, and moved on leaving stonehenge only partially pulled down

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If you do manage to time-travel, maybe you can get back to me and tell me if those 3 stories i made are actually true or not