The badgir, or windcatcher, is a tower rising above a building with shafts open near the top to catch prevailing breezes and channel them down into the rooms below, providing passive cooling without machinery. Long used across the arid Iranian world and the Gulf, it works by funnelling wind downward and, when still, by drawing warm air up and out through natural buoyancy, often passing the inflow over a cistern or qanat channel to chill it. The city of Yazd, called the City of Windcatchers, retains hundreds of badgirs, the oldest dating from the fourteenth century. The towers became a defining feature of the skyline in hot, dry settlements.
The windcatcher made dense settlement habitable in extreme desert heat using only wind and water, an early systematic technology of passive climate control. As a low-energy cooling principle it is now studied and revived in sustainable architecture for hot climates.