This grandiose 2C-1C BC sanctuary, one of the best examples of Hellenistic architecture in Italy, originally occupied a succession of terraces. From the lower temple, on what used to be the forum, a basilical room still stands, along with two side buildings, a natural grotto and the apse where the mosaic of the Nile was discovered. The upper temple, on the present-day Piazza della Cortina, is occupied by the Palazzo Barberini, which houses the museum.