Tunnel of Eupalinos

Around 530 BC the engineer Eupalinos of Megara drove a tunnel 1,036 metres through Mount Kastro to bring spring water into the city of Samos, and he did it by starting from both ends simultaneously, a feat of surveying that Herodotus listed among the greatest Greek works. The two crews met with an error of only a few metres, corrected by a deliberate dog-leg that is still visible where they joined. Below the walking tunnel runs a separate channel that carried the clay pipes, deepening gradually along its length to keep the water flowing. Restoration has opened progressively longer sections, and visitors can now walk either a short stretch or, on the full ticket, most of the tunnel's length, wearing hard hats through the low and narrow parts.

What you actually see

• The meeting point - the dog-leg where the two crews joined their headings.
• The water channel - the deep trench that carried the clay pipes.
• The tool marks - chisel work on the rock walls from the sixth century BC.
• The full traverse - on the long ticket, most of the kilometre of tunnel.

When to go

Spring and autumn; the tunnel is cool inside year-round. Numbers are limited and the full route requires booking ahead in season, particularly for the longer visit.

Honest expectations

The passage is narrow, low in places and unsuitable for anyone claustrophobic or with mobility difficulties; hard hats are required and bags must be left. Lighting is limited. The visit is guided and timed.

Nearby

Pythagoreion is below the hill; the Heraion lies across the plain to the west.