It is believed that by 400 BC, in Persia, engineers had found out a way to store ice for the whole year. What looks like a domed-shaped one, the traditional cooler was called Yakhchāl. It means ice pit in Persian language.
The people would either bring ice from the nearby mountains; if not, channel the water to the Yakhchāl. This man-made cooler is said to be located away from the city and is often about 18 metres high.
It was used not just to store ice, but also for food.