🇮🇷 Iran · Hydraulic works
Qanat of Gonabad
Achaemenid to Sassanian (~700 BCE – 300 CE) · Persian (Achaemenid, Sassanian)
Possibly the oldest and deepest qanat in Iran, the Qasabeh Qanat of Gonabad extends 33 km with a mother-well 300 m deep — the deepest vertical shaft ever hand-dug.