31.1267°N, 53.2853°E.
Domed mud-brick ice house in the desert town of Abarkuh, Yazd Province, central Iran. The Yakhchal of Abarkuh is among the best-preserved examples of yakhchal architecture, the Iranian engineering tradition for storing winter ice through the brutal summers of the central plateau. The structure consists of a tall conical dome — typically 12 to 18 metres high — built of mud-brick bonded with sarooj, a traditional Iranian mortar of sand, clay, egg whites, lime, goat hair, and ash that is impermeable to water. Beneath the dome lies a deep underground storage pit; long shading walls channel cold winter winds across shallow freezing pools whose ice was cut and packed into the pit. The technique dates back at least to the Achaemenid period and was systematized in the medieval Islamic era. The conical form and porous mud-brick exterior together produce evaporative cooling that maintains internal temperatures well below ambient.
Persians stored summer ice in a desert without electricity for two thousand years.