The Vasca was a large rectangular enclosure of about 85 feet by 120 feet. A 12-foot-wide roofed portico, open to the inside, surrounded a bathing area paved with inverted ceiling tiles (visible at far left in the photo). The bathing area was fed by an underground spring. Today the stream bed can still be seen in the Vasca—the muddy channel leading to pooled water at left-center in the photo.
Excavators also uncovered a small temple (20 feet wide and 10 feet deep), or sacellum, at the western side of the pool. This temple is visible as a squarish protuberance at right in the photo. Ailing visitors likely entered the pool at one corner and exited at the opposite corner after making an offering at the temple, which once contained a cult statue.