The ancients were cleverer than some people today assume. They didn’t have rockets or electricity, at least no indisputable proof has been found of such technologies, but they did come up with technology that we don’t usually associate with the ancient world. The yakhchal (meaning ice pit) was a type of ancient refrigerator built in the deserts of Persia (now Iran), which was made without electricity, modern coolants, or most elements of modern refrigerators. It demonstrates the ability of humans to find solutions to problems with any materials or technology they have available.
This approach to making refrigerators was mastered by Persian engineers around 400 B.C., though it is possible that people were making them before that. Yakhchals are fairly simple to make so that even those who were relatively poor could afford them. Most yakhchals were domed structures with an underground square-shaped containment area. After the containment area was dug and the dome was erected, a type of mortar made from clay, sand, ash, goat hair, and lime called sarooj was used to make it waterproof.
H/t reader kevin a.
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