The tower of Olynthos, also known as the Tower of Mariana, is located just two kilometres north of the town of Olynthos, to the left of the country road to Polygyros.
It is one of the most characteristic examples of the Byzantine tower in the region; its builders used not only stone but also tiles, bricks and architectural fragments from the remains of ancient Olynthos.
The tower was built in 1374 and by the monks of Dochiariou Monastery, acting as a focal point and defense for the dependency of the same name. A characteristic feature is the cross formed of tiles set into the masonry of the southern wall, which confirms the ownership of the tower. It still exists today to a height of about 15m.