29.4536°N, 55.6618°E.
The Sirjan Twin Icehouses are a pair of conical mud-brick yakhchāl in Kerman Province, southeastern Iran, built during the Safavid and Qajar periods to store winter ice through the summer. Each dome rises roughly 18 metres above a sunken pit, with walls up to two metres thick at the base composed of sarooj — a traditional waterproof mortar of clay, egg whites, lime, goat hair, and ash. The shaded northern flank holds a long east-west wall that froze shallow channels of water on winter nights; blocks were then transferred into the pit and insulated by the dome's chimney effect, which vented warm air upward and drew cool air across the ice. The two domes stand within sight of each other on the desert floor, and the village around them was largely organised by the seasonal trade in their contents.
They are refrigerators that ran on geometry, in a place where summer surface temperatures regularly exceed 45 °C.