Muel Dam
The 928th tallest dam in the world
The Muel Dam was a Roman gravity dam in Zaragoza province, Aragon, Spain, dating to the 1st century AD. The resulting reservoir in Muel, fed by the Huerva River, was created during the time of Augustus in the early 1st century. It served to provide water to the Colonia Caesaraugusta, present-day Zaragoza, which had been founded shortly before.
Dam data from Wikidata (CC0) plus curated additions. Summary from Wikipedia (CC BY-SA).