The Antikythera wreck

Sponge divers sheltering from a storm in 1900 found a Roman-era wreck off this small Greek island, and the salvage produced bronze and marble statues, glass, jewellery and a corroded lump of gears. That lump was the Antikythera mechanism: a geared analogue computer, built around the 2nd century BC, that modelled the sun, moon and planets and predicted eclipses. Nothing of comparable complexity appears again for well over a thousand years. Divers are still working the site and still recovering material. The mechanism is in the National Archaeological Museum in Athens.