The world’s largest stone arch is 65 meters long and is located in Lisbon—but the visible section represents less than 2% of the Águas Livres Aqueduct, a 58-kilometer system that withstood the 1755 earthquake
The monumental arches spanning the Alcântara Valley are the hallmark of the Águas Livres Aqueduct, designated a National Monument since 1910, but they represent only a small fraction of the entire netwo...