Tunnel of Eupalinos

Just north of the ancient city of Pythagoreion on Samos, a tunnel more than a kilometre long runs straight through the centre of a hill, and it was dug by hand about 2,500 years ago. The Tunnel of Eupalinos, named after the engineer from Megara who designed it, was built in the sixth century BCE, under the tyrant Polycrates, to bring fresh water from a spring on the far side of Mount Kastro into the city. The tunnel is about 1,036 metres long, and it is recognised as one of the great engineering achievements of the ancient world. It forms part of the UNESCO World Heritage listing of Pythagoreion and the Heraion of Samos.

What makes it extraordinary is the way it was built. The workers dug from both ends at the same time, aiming to meet in the middle of the hill, with no modern surveying instruments. Eupalinos planned the route with such care that the two teams met with only a small error in alignment, and a slight kink in the tunnel marks the spot. The Greek historian Herodotus described the tunnel as one of the three greatest works in the Greek world, along with the temple of Hera and the harbour mole. A channel dug along the floor carried the water, which flowed in a pipe, while the main passage served the workers and later maintenance.

Today visitors can enter a section of the tunnel by a staircase near the northern entrance, and walk a short length of the original passage. The tunnel is narrow and low, about the width of a person, with rough walls marked by pick strokes and lit by modern lamps. A small corridor leads to the sloping channel, and visitors can see the water channel and the point where the work of the two teams joined. The tunnel is cool inside, a pleasant change from the summer sun, but visitors who dislike enclosed spaces may find it tight.

Access is by a short walk from the ticket booth near the entrance, and tours or entry times can be limited, so it is wise to arrive a few minutes early and check the current schedule. The tunnel is a short taxi ride or drive from Pythagoreion, and there is some parking nearby.

It makes a good pair with the ancient harbour and city of Pythagoreion, the nearby Heraion and the archaeological museum in Vathy. A visit takes about 30 to 45 minutes, and it gives a vivid sense of how ancient engineers solved problems with ingenuity and patience.