The archaeological park is one of the most beautiful places in the city and along the coast of Posillipo. Among the most important sites are the Seiano cave, the underwater park of Gaiola, the imperial villa of Pausilypon, the Odeon, the theatre and the Palace of the Spirits.
The ruins of the Roman villa of Vedius Pollio, also known as the Imperial Villa, include a 2000-seat theatre on the rocky promontary at the end of the Bay of Naples. Some of the villa's rooms can be seen with traces of the wall decorations while its marine structures and fish ponds are now part of the neighbouring submerged Gaiola Park. The villa was built in the first century BC by Publius Vedius Pollio. On his death in 15 BC, the villa was bequeathed to Augustus, and remained in imperial possession for his successors at least until Hadrian, as witnessed by a stamped water pipe. In various points the presence of water supply pipes (coated with hydraulic mortar) show the opulence of the facilities. Augustus demolished at least part of the house and constructed in its place a colonnade in honour of his wife Livia, which he dedicated in 7 BC.
The Palace of the Spirits is an archaeological complex on the coast near Marechiaro and was the nympheum of the villa and also built in the first century BC. The submerged parts of the ruins of the imperial villa and the rich and diverse marine and coastal natural environment can be seen via boat excursions.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.