The extensive wall known as “Dema” or “Desis” is located to the northeast of Aspropyrgos and about 2.5 km to the west of Ano Liosia, in the narrow passage between Aigaleo and Parnes. Dema, built to protect the strategic passage between Acharnes and the Thriasian Plain, was almost 4.5 km in length. It was constructed of rough-hewn polygonal blocks. Its erection is generally placed in the first half of the 4th century.