A conic hill rises at the junction of the Kasaba and Tokluca rivers at the mouth of the Demre Valley. An important classical citadel, called the Dereağzı Fortress stands on the top of this hill. Some Lycian rock-cut tombs are on the left side of the river on the northeast side of the hill.

About 1km northeast of the Dereağzı Fortress, on the Kasaba plain next to the gravelly river is a large church of the 8th or 9thC. The plan is of a dome over a cross, with octagonal chapels on either side of the nave and the materials are stone with bands of brick, and brick for the dome (which has fallen). Some walls were marble-clad and there were once frescoes and mosaics.