In the Greek islands, the Antikythera shipwreck yields statues, human teeth and the missing head of Hercules In 1900, sponge divers working near the Greek island of Antikythera accidentally discovered a 2,000-year-old mystery.

Dressed in a canvas suit with a helmet made of copper, Elias Stadiatis plunged through the cool ocean depths, in search of the soft sponges he had spent his career gathering.

But as he reached the rocky bottom at a depth of about 50 metres, he uncovered a long-forgotten tragedy.

Hidden between layers of debris on the ocean floor were what appeared to be rotting corpses and horses.

Stadiatis immediately began signalling to the crew above and was soon dragged back to the surface, apparently shaking with fear and mumbling about "seeing a heap of dead people".

They feared Stadiatis was delirious, suffering from nitrate poisoning or seasickness ...