Just a few hundred meters west of the spring and pool of el-Zerqa, on the south bank of Nahr el-Assi, are a series of caves connected by stone steps. The main cave located 100 meters above the spring is known as the Monastery of Mar Maroun (Cave of the Monks). Originally thought to be constructed for builders working on the canalization channels and Hermel pyramid in 200 BC, it became a place of sanctuary in 425. Following the massacre of its monks, the monastery was destroyed by Justinian II in the seventh century.