A corroded mechanism recovered by sponge divers from a sunken wreck near the Greek island of Antikythera in 1902 changed the study of the ancient world forever.
The Antikythera Mechanism, a system of bronze gears from the 2nd century BC, was used to calculate the date of the Olympic Games based on the summer solstice.
Its mechanical complexity was unequalled for 1,000 years, until the cathedral clocks of the Middle Ages.
Archaeologists believe hundreds more wrecks beneath the eastern Mediterranean may contain treasures, but a new law opening Greece's coastline to scuba diving has experts worried that priceless artifacts could disappear into the hands of treasure hunters.
"The future of archaeology in this part of the world is in the sea," said marine archaeologist Harry Tzalas. "This law is very dangerous, it opens the way to the looting of antiquities from the seabed which we don't even know exist."
Greece's 1932 antiquities law says all artifacts on land and in the sea belong to the state, but it does not regulate scuba diving, developed in the 1940s by Frenchman Jacques Cousteau.