During the civil wars Cumae was one of the strongholds that Octavian used to defend against Sextus Pompey. Under Augustus extensive public building works and roads were begun and in or near Cumae several road tunnels were dug: one through the Monte di Cumae linking the forum with the port, the Grotta di Cocceio 1 km long to Lake Avernus and a third, the "Crypta Romana", 180m long between Lake Lucrino and Lake Averno. The temples of Apollo and Demeter were restored.