The palaestra is an open space surronded by a colonnade.
This is where the Romans would take some time to greet friends and participate in some of the popular exercises such as: throwing a large ball, wrestling, and fencing with wooden swords
From the palaestra, the Romans would then walk along a passage into a large hall known as the apodyterium, or changing-room.
This is where they removed all their clothes and handed them over to one of the slave attendants, who would then place them in one of the niches arranged in rows along the wall