The famous tunnel of Efpalinus, which is at Pythagorion, was the "eight wonder" of the ancient world. The way which it is constructed often comes as a surprise even to modern experts. The success of the enterprise - given the means available at the time: the hammer and the chisel - is astonishing.
This tunnel is the middle section of a major aqueduct, constructed around 550 BC by the architect Efpalinus, to supply the ancient city of Samos, the modern Pythagorion, with water.
Its construction took about ten years and the tunnel has a length of 1.036 meters. In order to construct the conduit, a total of 7.000 cubic meters of natural rock had to be removed. The section of the tunnel is on average 1.80 by 1.80 meters, and it cuts through the mountain at a depth of 180 meters below its summit. This ancient tunnel is constructed with rectangular stones which are very skillfully fitted one on top of the other.
It is roofed with a triangular vault, made with same kind of stones. The persistence of the ancient Greeks, who in this section were faced with doubly difficult tasks, still calls forth the admiration of the visitor.
They first had to hallow out the mountain and then construct in it the wall and vaulted corridor as a passageway. The water was channeled through pipes which were installed in the aqueduct below the part of the tunnel in the direction of the source and alongside it in the direction of the town.
These pipes, which remain at many points, are so well made that they were put in yesterday, even after the passage of so many centuries and all this without any of the technological means available to our own age. The tunnel is lit and accessible to visitors.