Harbaqa Dam
The 928th tallest dam in the world
The Harbaqa Dam or Kharbaqa Dam was a Roman era Palmyrene gravity dam in the Syrian Desert about 70 kilometres (43 mi) southwest from Palmyra on the road to Damascus. The dam, built of rubble, concrete, and dressed with ashlar stones, dates to the first or second century AD. The dam later was used as a water supply for the Umayyad palace of Qasr al-Hayr al-Gharbi.
Dam data from Wikidata (CC0) plus curated additions. Summary from Wikipedia (CC BY-SA).