The indigenous architecture of Iran is a distinct architectural genre characterized by the use of clay and mud-brick as the main building materials. It is also credited for the use of vaulted ceilings by the use of mud-bricks, clay,and baked brick. This genre of architecture is rooted to the Sumerian time (c. 5000 B.C.). Indigenous architecture of Iran has some noted characteristics or landmarks or features. Such features may be classified as: 1) maj-moo’ah (a complex, a group, or a set; a group of public buildings such as a mosque, a theological school, a tea-house, a baazaar, and a ground water reservoir in one section of a city within a short walking distance near to each other); 2)traditional houses with traditional wooden doors; 3) koochehe (a narrow alleyway) and clay buttress (kheshti saabaat); 4) baadgeir ( a wind-catching tower);5) traditional tiles and tile-works;6) muqarnass decoration for a vault; 7) baazaar or the traditional shopping center; 8) caravansaries, as stopping lodges in the ancient silk road, for the caravans that were carrying goods and travelers from China to Syria and that were passing through Iran; 9) Castles of Iran; and 10) Palaces of Iran; and 11) art works including wall paintings in the palaces. From about mid-20th century, however, many features of the indigenous architecture of Iran have been abandoned or demolished to be replaced by modern and multi-story buildings. The present series seeks to bring to the attention of viewers both a record and a pictorial introduction of the main features of the indigenous architecture of Iran as a unique architectural genre that is weathering a strong wave of modernization. Volume IV of this series, therefore, is about the baadgeir (translated as: a wind-catching tower) in the historic cities of Iran.