Sanctuary of Pan
From Project Athinai
The sanctuary of Pan was created, after the victory at Marathon, in two adjacent caves on the northwest slope of the Akropolis around 485 BC. The shallower cave was covered with votive reliefs carved in the rock. One niche probably housed the cult statue of Pan.
Camp, John M.; The Archaeology of Athens, Yale University Press, 2001, pp. 119-120
Hurwit, Jeffrey M.; The Acropolis in the Age of Pericles, Cambridge: Cambridge University Press, 2004
Travlos, John, Pictorial dictionary of Ancient Athens, Books that matter, New York, 1971, p. 417