The Galleria Borbonica, Tunnel Borbonico or Bourbon Tunnel is an ancient military underground passage connenting the Royal Palace to military barracks in Naples, enabling the king to flee to the sea and the soldiers to defend the palace quickly.
Errico Alvino was commissioned to construct a military passage for troops. Two years after it was begun, the fall of the Bourbon dynasty led construction to halt. The underground halls and floors were originally tuff stone pits and also contained old water cisterns. During the hundreds of bombings in World War II the people of Naples used the rooms as shelters. Being forgotten the tunnel system became a depot for illegal cars and bikes confiscated by the police in the 1920s/1930s. The tunnel contains decades of debris, including vintage cars and a discarded fascist monument that had been made for Aurelio Padovani. Since 2014 the tunnels are open for touristic tours.