Alongside the sea are the remains of impressive artwork from the imperial era, which tradition identifies as the tomb of Agrippina, mother of Nerone. It is, in reality, a theatre-nymphaeum belonging to a large maritime villa that has now been destroyed. This structure, originally an odeion (theatre for music or shows) dating back to the Augustan or Giulio-Claudia age, was transformed into an exedra nymphaeum between the end of the 1st and the beginning of the 2nd century AD. The monument consists of three hemicycles arranged on several levels: the first is about one and a half metres below the current beach level, the second is protected by a ramped vault, on which the steps in opus reticulatum are still visible, three openings interspersed with windows adorn the outer wall. At a lower level is another hemicycle, the vault of which has collapsed and whose inner wall is marked by stucco half-columns with Corinthian capitals, divided into small rooms by transverse partitions. The vault and walls of the niches and windows, as well as the corridor that originally connected the building with the villa, are decorated with stucco.