Tomb of Baba Rokn ud-Din which belongs to Safavid era, is located in Takht-e-Foolad Complex in Isfahan. It is completely unique and different from other buildings in Takht-e-Foolad Complex in terms of designing, architecture, details of building and dome and it is of special importance. One of the remarkable properties of the building is the use of some numerical symbols like five in the plan and twelve in the dome which seems an evidence and a representation of showing its respect and devotion to the five holy figures in Islam and twelve Imams of Shi'a. Due to the outdoor location of this tomb which is visible from all sides, architects tried not to use external tall walls with multiple arches to decrease simplicity and make it better-looking by adding tiling adornments in spandrels of the arched dome. First, there have been some excellent enamel tilings in the interior and exterior of the building most of which are destroyed now. The entrance is located in northeast- side of the tomb that includes a high porch and an inscription with white thuluth script on ultramarine tiles made by the prominent  calligrapher, Mohammad Saleh Isfahani in Abbas I of Persia Era. This monument has been registered as one of the national monuments of Iran.