The Piazza Duomo Hypogeum is an underground tour linking the Piazza del Duomo east-west to the Marina walls. It consists of a main gallery with other secondary galleries, one of which leads to the large cistern of the Archbishop's Palace. Bishop Paolo Faraone (1619-1629) oversaw its construction, a fundamental element not only for the water supply of the Archbishop's Palace, but for all of Ortigia. Along the route you will be able to admire the remains of wells and cisterns destroyed during excavation work. The original hub of tunnels is connected to an earlier quarry located in Piazza Duomo, whose stone was used for the façade of the Cathedral and is mentioned in an 18th-century document. In 1869, during the course of public works, an access was found, located "almost opposite the entrance gate of the archiepiscopal palace, but giving a little to the side of the Monastery of S. Lucia". The Second World War brought attention back to the underground chambers of the previous century: following Italy's joining the war, provision was made for gathering points for the civilian population in the event of an attack. Additional spaces were added inside the old quarry in Piazza Duomo, one of which had a room to store the simulacrum of Santa Lucia and the treasure, hidden since December 1942, in zinc boxes. A connection was then made between the cathedral square and the Marina via a north-south side tunnel, joined to the cistern. With the war over, the shelters closed down. The air-raid shelter in Piazza Duomo, which testifies to Ortigia's millenary urban history, constitutes a single complex that brings together contributions from different phases of the city's history, with the cistern as the chronologically oldest element.