The existence of the Antikythera mechanism should call into question how deep our knowledge really is about the ancient world. Made in Greece, it was about 1500 years ahead of its time, and is the first known analog computer. Was it the work of a mega-genius or was it something that only the wealthy could afford but hardly unusual for the time. Before it was found, we assumed that devices of its sophistication didn't exist until the 14th century.