25 km/16 mi south of Pórto Ráfti is Keratéa or Kakí Thálassa. Beyond this, to the left of the road to Lávrion, is the site of ancient Thorikos (28 km/17 mi), on a hill on the north side of Lávrion Bay which was fortified in 490 B.C., during the Persian wars. There was a settlement here in Mycenaean times, as is shown by two nearby tholos tombs
(between the two summits of the hill and on its eastern slopes).
The most notable structure on the site is the theater (fifth-fourth century B.C.), which belonged to a sanctuary of Dionysos. It is of rather archaic type, with an orchestra which is neither circular nor semicircular, as was the usual style, but almost rectangular. In consequence the auditorium also departs from the usual circular form.