In the area of Loimikos, in the northern part of the mountain range of Parnitha, there is a fryktoria-observatory of the first half of the 4th c. BC, known as Loimikos Tower. The purpose of its establishment must have been the surveillance of the road that came from the plain of Tanagra and led from the eastern passages to Athens.

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.