Bam Citadel which has been registered on UNESCO’s World Heritage List was the largest adobe building in the world, located in Bam City in Kerman Province. 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 the same place of citadel itself, but because of the impressive look of the citadel, which forms the highest point, the entire fortress is named the Bam Citadel. Reliable sources from the 10th century AD show that it has been founded some 2,000 years back, and has been repeatedly repaired thereafter. On December 26, 2003, the Citadel was almost completely destroyed by an earthquake, along with much of the rest of Bam and its environs.