The Tower of Silence
Zoroastrians revere the air, earth, fire and water. Burying someone in the earth pollutes it. Cremating someone pollutes the air. So to avoid this when someone died they used to prepare the body (in the buildings in the foreground) and then leave it exposed in the tower on top of the hill. Vultures would strip the flesh and then after a few days the bones would be collected and buried.