Imagine a place right here on Earth—not on Mercury or Venus—where it’s not particularly unusual for the summer temperature to soar to 180 degrees Fahrenheit (82 degrees C). Now imagine a 20-meter or 60-foot-tall building in that hellish place where ice can be safely stored, completely frozen, for the entire summer. Oh—I should also add that the building has no electricity and is made out of mud, goat hair, ash, and egg whites.

These buildings exist, and they’re called Yakhchals. They’re found in the Middle East, mostly in Iran, in places where it gets very cold in the winter, when ice can be made, and very hot in the summer. They’re a type of evaporative cooler—in the dry parts of the American south, a similar technology is called a swamp cooler—and these Yakhchals been in continuous use since at least the fourth-century BCE.