Alcantarilla Dam

The Alcantarilla Dam is an ancient Roman gravity dam built to supply water to the Roman city of Toletum (present-day Toledo, Spain), in the Roman province of Hispania Tarraconensis. It was constructed in the 2nd century BC on a tributary of the Tagus River. Currently in ruins, it is located between the towns of Sonseca and Mazarambroz (Toledo). It is believed to be the oldest dam in Spain and possibly the oldest known Roman dam. The toponym "Alcantarilla" means conduit and is of Arabic origin: its Latin name is unknown. It was 20 metres (66 ft) high and at least 550 metres (1, 800 ft) long. The water was conveyed to the city by an aqueduct which passed through Layos.

Dam data from Wikidata (CC0) plus curated additions. Summary from Wikipedia (CC BY-SA).