The Crypta Neapolitana is an ancient Roman tunnel near Naples. It was built in 37 BC, and is over 700 metres long.
The tunnel passes beneath the Posillipo hill and connects Naples with the so-called Phlegrean Fields and the town of Pozzuoli along the road known as the via Domiziana.
The eastern Piedigrotta entrance is now enclosed within an archaeological park, and the site of the villa of Vedius Pollio, and later imperial villa. The site is also noteworthy for the presence of the so-called Virgil's tomb, as well as the tomb of the Italian poet Giacomo Leopardi. Three secondary tunnels end in openings overhanging the bay, providing light and ventilation.
The name Grotta Seiano (Sejanus's cave) comes from the infamous Lucius Aelius Sejanus, prefect of Tiberius, who according to tradition, commissioned its enlargement in the first century AD. The first tunnel was built by the architect Lucius Cocceius Auctus for Agrippa during the civil war between Octavian and Sextus Pompeius in c.37 BC to connect the villa of Vedius Pollio and other patrician villas of Pausilypon (ancient Posillipo) to the ports of Puteoli and Cumae. The tunnel is one of a number of such works in the Naples area built by Cocceius.
The tunnel was still in use as a roadway until superseded by two modern tunnels in the early 20th century, and shows extensive restoration done by the architects of the Bourbon dynasty of Naples. During the Second World War it was used as a bomb shelter for the inhabitants of Bagnoli; the war and some landslides during the fifties put it back into a state of neglect. Today it has been restored as an archaeological site.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.