Ice house dome, main wall and a little pool. In Yazd province, during the winter when there was sufficient water, it was led to the little pools. During the night due to low temperatures the water of these pools used to freeze. A tall wall surrounded the pool that prevented sunlight from getting to the ice and created a condition for ice-layers to thicken gradually at nights. Then the ice was broken and transferred to the icehouse underground where it was stored in summer.