The Antikythera mechanism (pronounced /ˌæntɪkɪˈθɪərə/ AN-ti-ki-THEER-ə), is an ancient mechanical calculator (also described as the first known mechanical computer) designed to calculate astronomical positions. It was recovered in 1901 from the Antikythera wreck but its complexity and significance were not understood until decades later. It is now thought to have been built about 150–100 BC. Technological artifacts of similar complexity did not reappear until a thousand years later.
The first to lay eyes on the shipwreck 60 metres down was Elias Stadiatos, who quickly signaled to be pulled to the surface. He described the scene as a heap of rotting corpses and horses lying on the sea bed. Thinking the diver had gone mad from too much carbon dioxide in his helmet, Kondos himself dove into the water, soon returning with a bronze arm of a statue. Until they could safely leave the island, the divers dislodged as many small artifacts as they could carry.
Together with the Greek Education Ministry and Hellenic Navy, the sponge divers salvaged numerous artifacts from the waters. By the end of 1902, divers had recovered statues of a philosopher's head, a young boy, a discus thrower, the bronze Antikythera Ephebe of ca. 340 BC (now in the National Archaeological Museum of Athens), a Hercules, a marble bull and a bronze lyre. Many other small and common artifacts were also found. On 17 May 1902, however, archaeologist Valerios Stais made the most celebrated find. When diving to search the area of the wreck, he noticed that one of the pieces of rock near him had a gear wheel embedded in it. It would soon be identified as the Antikythera mechanism; originally thought to be one of the first forms of a mechanised clock, it is now considered to be the world’s oldest known analog computer.