This photograph shows the remains of the caldarium (hot bath) of the public bathhouse. The floor of this room, now gone, was originally placed on the more than 200 columns seen here. The floor itself was probably a mosaic.

The walls were faced with vertical rows of clay pipes through which hot air flowed from under the floor up and into the room. The hot air included steam from the water pipes. The caldarium functioned much like a sauna.