2 Best Sights in Pythagorio, The Northern Aegean Islands

Considered by Herodotus as the world's Eighth Wonder, this famed underground aqueduct was completed in 524 BC with archaic tools and without measuring instruments. The ruler Polycrates, not a man who liked to leave himself vulnerable, ordered the construction of the tunnel to ensure that Samos's water supply could never be cut off during an attack. Efpalinos of Megara, a hydraulics engineer, set perhaps 1,000 slaves into two teams, one digging on each side of Mt. Kastri. Fifteen years later, they met in the middle with just a tiny difference in the elevation between the two halves. The tunnel is about 1,018 meters (3,340 feet) long, and it remained in use as an aqueduct for almost 1,000 years. More than a mile of (long-gone) ceramic water pipe once filled the space, which was later used as a hiding place during pirate raids. Today the tunnel is exclusively a tourist attraction, and though some spaces are tight and slippery, you can walk the whole length—a wonderful way to enjoy natural coolness on swelteringly hot days—or part sections. On a hillside above the tunnel entrance are the scant remains of a Greek and Roman theater, and ancient city walls.

At the eastern corner of Pythagorio lie the crumbling ruins of the Kastro, probably built on top of the ruins of an older acropolis. Revolutionary hero Lykourgou Logotheti created this 19th-century edifice; his statue is next door, in the courtyard of the church built to honor a victory. He held back the Turks on Transfiguration Day, and a sign on the church announces in Greek: "Christ saved Samos 6 August 1824." On saint days the villagers light votive candles in the church cemetery, a moving sight with the ghostly silhouette of the fortress and the moonlit sea in the background. Nearby are some fragments of the wall that the ruler Polycrates built in the 6th century BC.