Khirki Masjid is approached from the Khirki village in South Delhi and close to the Satpula or the seven arched bridge on the edge of southern wall of Jahapanah (the fourth city of Medieval Delhi), was a mosque built by Khan-i-Jahan Maqbul Tilangani, the Prime Minister of Feroz Shah Tughlaq.
The Masjid, which is in a quadrangular shape, was built as a fortress with an unusual fusion of Islamic and traditional Hindu architecture.
It is said to be the only mosque in North India, which is mostly covered; the totally covered mosque of the Sultanate period.
Web : http://en.wikipedia.org/wiki/Khirki_Masjid