32.8611°N, 53.0860°E.
The Nain Historic Qanat District sits at the edge of the Dasht-e Kavir in Isfahan Province, central Iran, and is one of the oldest continuously operating qanat systems on the Iranian Plateau, with shafts and galleries dated to the Sasanian period and earlier. A qanat is a gently sloping underground tunnel that taps an alluvial aquifer at the base of a mountain and carries the water by gravity to the surface kilometres away, with a chain of vertical shafts above it for ventilation and spoil removal. Nain's network feeds the Friday Mosque, the Pirnia traditional house, and a dense lattice of courtyard gardens, and is paired locally with wind towers that pre-cool the water as it surfaces. The Nain Historic Qanat District remains in use, with hereditary mirab water-masters still allocating flow by traditional time-share.
From the air the shaft heads form a dotted line across blank desert, like a buried ruler.