The Sultan Sanjar Mausoleum was built in the ancient Silk Road oasis city of Merv in the 12th century. Believed to be the largest city in the world, Merv boasted a population of over one million in medieval times.
According to local legend, Sultan Sanjar fell in love with a peri (fairy) who agreed to marry him on three conditions: he could never look at her feet when she walked, never gaze at her while she combed her hair, and never touch her waist. Violating her request, Sanjar discovered that she walked without touching the ground, removed her head to comb her hair and had no bones in her waist. Infuriated, the beautiful peri flew away. Sanjar begged to see her again. The peri promised to come if he would build a beautiful building with a hole in the roof to look through. After he died, he was buried there so that the peri would look inside and see his grave until the end of time.