Eupalinean Aqueduct

The Eupalinian Aqueduct is a unique engineering work of antiquity, hewn through Mount Kastro on Samos to supply the ancient city with water. Built around 550 BC by the architect Eupalinos of Megara under the tyranny of Polycrates, it stands out for its “amphistomon” method of tunneling—excavated simultaneously from two opposite directions—a construction challenge rarely attempted at the time. The tunnel is 1,036 meters long and its precision is considered a marvel of ancient Greek engineering. It formed part of a larger aqueduct with a total length of 2,385 meters and remained in use for about a millennium. Today it is one of the island’s top sights and is inscribed on the UNESCO World Heritage List.