These artificial caves on the slope of the hill are commonly called "Prison of Socrates", but they were surely not (the prison presumably used to jail him is situated in Agora).
If you look into the cave, it looks as this (right).
The many holes on the surface of the rock (see above) were used to sustain wooden beams. There must have been a two- or three-story structure in front of these caves. It is now known when they were made, nor what was the nature of the building.
During the WWII, these caves were used to hide the tresure from the Acropolis and the National Archaeological Museum; the surface was then covered with thick concrete.
