Sadd el-Kafara
The 928th tallest dam in the world
Sadd el-Kafara ("Dam of the Infidels") was a masonry embankment dam on Wadi al-Garawi 10 km southeast of Helwan in Cairo, Egypt. The dam was built in the first half of the third millennium BC by the ancient Egyptians for flood control and is the oldest major dam in the world. Never completed, the dam was under construction for 10–12 years before being destroyed by a flood. It was rediscovered by Georg Schweinfurth in 1885.
Dam data from Wikidata (CC0) plus curated additions. Summary from Wikipedia (CC BY-SA).