Analyzing the Architectural Features of the Fortresses on the Western and Southern Boundary of Kerman’s Lut Desert

Lut desert is located in southeastern Iran. The area, despite having many historical monuments, including numerous castles, has not received enough attention from architectural historians. This study aims to clarify the architectural features and the purpose for the multiplicity of these fortresses in this region, it has been tried to study and investigate them with descriptive, analytical, and logical cognitive methods. The research was carried out by library and field studies of 140 castles, as case studies, in the region. The study’s results show that the climate and security factors are the main reasons for erecting the castles. Abundant water and location on the trade routes made the region rich, and on the other hand, point water sources and their limitations caused dispersion and distance between the structures and increased insecurity. According to historical sources, desert outlaws have also had a large presence in the region.  Besides, the techniques to deal with violent sandstorms had caused them to build cities and villages in the middle of high barriers, or to build a castle inside or around it for use in times of need, which caused the number of castles in the investigated area. This has also caused the majority of castles in the region to have residential functions and be built inside or around cities and villages, and other functions and establishments are less frequent. The architecture of the castles and defense fortifications of the region also follows the common architecture of the central plateau castles, excluding incomparable cases. So, most of the castles follow the square and rectangular geometry, and in some cases, the irregular, trapezoidal, and parallelogram geometry is derived from the climatic and contextual conditions. The materials used were canvas and due to the ease of construction, speed of mass production, lower cost and camouflage, mud and mud brick in plain fortresses, and stone in mountain ones. Most of the towers are built in the corners and the middle of the sides with observational, defensive, and structural functions, and in some cases, towers are seen in the middle of the castle with only observational functions. The fortresses’ defense structure mainly is based on the barrier and tower, and as the wealth and population of residential castles increased, more defense boundaries were added.