Pythagoreio · Greece

Tunnel of Eupalinos

Known locally as Ευπαλίνειο Όρυγμα

Remarkable sixth-century BCE water tunnel bored through Mount Kastro to supply ancient Samos.

Tunnel of Eupalinos Zach Marshall · CC BY-SA 2.0
Typical visit
1 hour 15 minutes
Setting
Indoor
Region
North Aegean
Last checked
8 Aug 2026

Why visit

Remarkable sixth-century BCE water tunnel bored through Mount Kastro to supply ancient Samos. The tunnel was engineered in the sixth century BCE under Polycrates and excavated from both ends of the mountain, meeting with impressive accuracy. Herodotus later singled it out as one of the great works of Samos. The visit is strongest when you focus on ancient engineering passage, rock-cut water channel and connection to pythagoreion.

What you will see

  • Ancient engineering passage.
  • Rock-cut water channel.
  • Connection to Pythagoreion.

History

The tunnel was engineered in the sixth century BCE under Polycrates and excavated from both ends of the mountain, meeting with impressive accuracy. Herodotus later singled it out as one of the great works of Samos.

Photographs

Zach Marshall · CC BY-SA 2.0 · full attribution on the image credits page.

Visitor tips

  1. 1

    Prioritise Ancient engineering passage if you have less time than the full suggested visit.

  2. 2

    Leave enough time for Rock-cut water channel rather than treating Tunnel of Eupalinos as a quick photo stop.

  3. 3

    Check the current island transport or ferry plan before fixing the day around Pythagoreio; seasonal services and final local connections can change.

About North Aegean

Byzantine monasteries, mastic villages, ancient Samos engineering, volcanic geology and island castles.

Open the Greece guide

Combine it with

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