Monument in Yazd
A wind Tower (wind catcher) or Badgir is a traditional Persian architectural element to create natural ventilation in buildings. Badgirs come in various designs: uni-directional, bi-directional, and multi-directional. The devices were used in ancient Egyptian architecture. Badgirs remain present in Iran and can also be found in traditional Persian-influenced architecture throughout the Middle East, including in the Arab states of the Persian Gulf (mostly Bahrain and the United Arab Emirates), Pakistan, and Afghanistan.
Central Iran shows large diurnal temperature variation with an arid climate. Most buildings are constructed from thick ceramic with high insulation values. Towns centered on desert oases tend to be packed very closely together with high walls and ceilings, maximizing shade at ground level. The heat of direct sunlight is minimized with small windows that face away from the sun.
The windcatcher's effectiveness had led to its routine use as a refrigerating device in Persian architecture. Many traditional water reservoirs (ab anbars) are built with windcatchers that are capable of storing water at near freezing temperatures during summer months. The evaporative cooling effect is strongest in the driest climates, such as on the Iranian plateau, leading to the ubiquitous use of windcatchers in drier areas such as Yazd, Kerman, Kashan, Sirjan, Nain, and Bam.
A small windcatcher is called a shish-khan in traditional Persian architecture. Shish-khans can still be seen on top of ab anbars in Qazvin and other northern cities in Iran. These seem to function more as ventilators than as the temperature regulators seen in the central deserts of Iran.