Tunnels of Claudius
The Tunnels of Claudius (Italian: Cunicoli di Claudio) consist principally of a 6 km-long tunnel (or emissary) together with several monumental service tunnels which Roman Emperor Claudius had built by 52 AD to partially drain the Fucine Lake in Abruzzo, protecting riparian villages from floods and creating agricultural land. It was a massive engineering project involving 30,000 workmen and slaves who completed it in just 11 years, and considered among the grandest in antiquity.