Davelis Cave, also known as Penteli Cave, is located on the south-western slope of Penteli.
At 720 metres high, the cave is located in an ancient, white Pentelic marble quarry to the north of Penteli Monastery. Because of the continual quarrying of marble, the cave has fallen into disrepair and its roof has partially collapsed.
Archaeologists believe that the cave served as a place of worship during antiquity, and evidence suggests that ascetic hermits were here, from the early Christian era until the founding of the Penteli Monastery. In the 11th century, the Agios Spyridon and Agios Nicolas chapels were built at the cave’s entrance and some of their 13th-century frescoes have been displayed at the Byzantine Museum.