This bizarre dial has been perplexing researchers ever since it turned up in an ancient Greek shipwreck. It's approximately two thousand years old, and some people call it the world's first computer.
It wasn't powered by electricity, but appears to have been operated by winding it up, like an early form of clockwork. We believe it could track the movements of celestial objects, including the Moon, the Sun, and the five planets the Greeks were aware of. Nothing so advanced would be invented for another one thousand years.