The Tower of St. Peter of the Hellenic era (4th – 3rd century B.C.) is one of the best preserved towers of Cyclades. It is a cylindrical building, 20 meters in height, and the diameter of the base is 9.40 meters. It is entirely constructed of local slate. There is an interior staircase that leads to at least five floors.

The tower is built on a very privileged position as it dominates the valley of Gavrio and overlooks the sea and the ships. Also, around the tower, you can find the ancient copper mines which were still in operation until the beginning of the century.

You can visit the tower daily. It remains open till sunset.