Three semicircular exhedras open onto a large, square hall. The central part is decorated with mosaics depicting the Twelve Labours of Hercules, but some of these are no longer visible. At the centre of the left semicircle the glorification of Hercules is portrayed, and in the central semicircle, an impressive Gigantomachy, a combat during which five giants are killed by Hercules's arrows. The legend of Ambrosia and Lycurgus is illustrated in the right semicircle.