This was the school for wrestlers and boxers and a place for them to live during the games. It was built during the Hellenistic period. The plan has a central courtyard surrounded by rooms of various sizes.
The courtyard was the training grounds and the rooms were for athletes to prepare.
To me, this has always seemed the most peaceful part of the site. That is not due to how the ancient building was used, but just the way vegetation has grown up around it now. 2012 image.