It was the largest adobe building in the world, located in Bam, a city in the Kermān Province of southeastern Iran. It is listed by UNESCO as part of the World Heritage Site "Bam and its Cultural Landscape". The origin of this enormous citadel on the Silk Road can be traced back to the Achaemenid period (6th to 4th centuries BC) and even beyond. The heyday of the citadel was from the 7th to 11th centuries, being at the crossroads of important trade routes and known for the production of silk and cotton garments.
The entire building was a large fortress in whose heart the citadel itself was located, but because of the impressive look of the citadel, which forms the highest point, the entire fortress is named the Bam Citadel.
On December 26, 2003, the Citadel was almost completely destroyed by an earthquake, along with much of the rest of Bam and its environs. A few days after the earthquake, the Iranian President Mohammad Khatami announced that the Citadel would be rebuilt.
The planning and architecture of the citadel are thought out from different points of view. From the present form of the citadel one can see that the planner(s) had foreseen the entire final form of the building and city from the first steps in the planning process. During each phase of building development the already-built part enjoyed a complete figure, and each additional part could be "sewn" into the existing section seamlessly.
The citadel is situated in the center of the fortress-city, on the point with widest view for security.
In the architectural form of Bam Citadel there are two different distinguishable parts:
The rulers' part in the most internal wall, holding the citadel, barracks, mill, 4-season house, water-well (dug in the rocky earth and about 40 metres [130 ft] deep), and a stable for 200 horses.
The ruled-over part surrounding the rulers' place, consisting of the main entrance of the entire fortress-city and the bazaar alongside of the North-to-South spinal axis (which connects the main entrance to the citadel), and around 400 houses with their associated public buildings (such as a school and sport place).
Among the houses, three different types are recognizable:
Smaller houses with 2-3 rooms for the poor families.
Bigger houses with 3-4 rooms for the middle social class, some of which have also a veranda.
The most luxurious houses with more rooms oriented in different directions suitable for different seasons of the year, together with a big court and a stable for animals nearby. There are few of this type of houses in the fortress.
All buildings are made of non-baked clay bricks, i.e. adobes. Bam Citadel was probably, prior to the 2003 earthquake, the biggest adobe structure in the world.
The Citadel was used as the major location site for Valerio Zurlini's film of The Desert of the Tartars.