A part of the gymnasium, the palestra was the main training ground for the youths and was connected to the xystos, used for the training of adult men. The depression in the center of the field was filled with water and used for the staging of naval battles (presumably on especially hot days). To the right of the palestra are two rows of gigantic stumps, the carbonized (by the eruption of Mt. Vesuvius) remains of plane trees, all close to three hundred years old at the time of their destruction. The image shows the Great Palestra of Pompeii. Greek equivalents were essentially similar.