While you are at it, maybe check out water tunnels ("Qanat") [0] and windtowers ("Bâgdir") [1] as well. I especially like the subterranean aqueducts - they required highly precise slopes to both reduce sedimentation (via high enough water speeds) and erosion (via low enough water speeds) at the same time.
[0] https://en.wikipedia.org/wiki/Qanat
[1] https://en.wikipedia.org/wiki/Bâdgir