The Hellenistic Tower of Agios Petros on Andros Island in Greece, Cyclades: The tower of Agios Petros is a quite well-preserved tower, placed on a hill overlooking the bay of Gavrio. It was probably built in the Hellenistic Era, in the 4th or 3rd century BC, and is 20m high. It has a cylindrical shape and was constructed by local schist. It used to have five floors, connected to each other with a helical ladder.
As we conclude from the area of its construction and its shape, the tower was built to overlook the above sea routes. People wanted to control the sea surrounding Andros island so that they could protect themselves and their villages from an enemy invasion or an attack by the pirates.
In fact, the area had copper mines, which worked from the ancient times till the mid 20th century, and was thus economically-developed. Therefore, the tower was useful to protect the mine workers and this source of richness for the island. The tower can be reached from Gavrio town. A 15 min drive and some walking are required to go to the top of the hill and get a view of this ancient tower.