Although known about by scholars (for example it is referred to in the Polish writer Adam Mickiewicz's epic "Pan Tadeusz" published in 1834), it had fallen into disuse over the centuries. it was rediscovered during works for a new road in 1841 and immediately brought to light and made passable by Ferdinand II of the Two Sicilies, becoming a tourist destination. Additional lining and arches were built to repair and reinforce the ancient walls. During World War II, it was used as an air raid shelter for the inhabitants of Bagnoli; the war and landslides during the 1950s took it back to a state of neglect since when it was restored.