Tower-Fryktoria, Mount Egaleo, Municipality of Petroupoli
Remains of a circular tower - fryktoria, with a diameter of 5.50m. and a height of 1.50 m., and its precinct at the top of Zacharitsa (altitude 452 m.) of Mount Egaleo in Petroupoli. It was built in order to receive messages from the west and send them to Athens and vice versa, as well as to monitor the wider area.
From this place the view is panoramic in all directions from the Saronic to Penteli (W-N) and from Parnitha to Athens (N-N). Some scholars associate it with the Demas wall and the Demas Tower, which it resembles in terms of construction. It dates back to the 4th century B.C.