Nagina Masjid or Gem Mosque is located in the north-western corner of the Macchi Bhawan in the premises of Agra Fort. An architectural marvel, this beguiling mosque was built by Shah Jahan between 1631-40. The mosque has a marble paved court surrounded by walls to the South, North and East. The prayer hall is found on the west. The main prayer hall of this mosque is built in pure white marble and oozes a pristine aura during sunny days. Bearing a very simple and decent decoration this mosque stands with three domes on its top and well adorned arches. Built for the ladies of the royal family as a private mosque this magnificent structure is 10.21 meter broad and 7.39 meter deep. A curve can be seen in the middle of the facade in the Chajja as well as across the parapet which makes the central part of the facade more prominent to look at. This architectural feature is known as bangladar and serves as a distinctive characteristic of this mosque.