The Crypta Romana is a tunnel dug into the tufa under the Cuma hill, crossing the acropolis in an east-west direction, giving an easier route from the city to the sea. Its construction is part of the set of military enhancement works built by Agrippa for Augustus and designed by Lucius Cocceius Auctus in 37 BC, including the construction of the new Portus Iulius and its connection with the port of Cumae through the so-called Grotta di Cocceio and the Crypta Romana itself.