Arrábida Bridge, arch bridge spanning the gorge of the Douro River between Porto and Vila Nova de Gaia, Portugal. Completed in 1963, the bridge carries a six-lane roadway 25 metres (82 feet) wide, supported 52 metres (170 feet) above the river. Its overall length of 493 metres (1,617 feet) includes a reinforced-concrete arch 270 metres (885 feet) long, which was the largest in the world at the time of its completion. Since 2016, tours have permitted pedestrians to traverse the archway with safety gear.