Built by the greatest Chauhan ruler Prithviraj Chauhan III, this landmark is also known as the first Red Fort of Delhi and one of the seven ancient cities of Delhi. Prithviraj Chauhan is credited to have extended the citadel of Lal Kot, and constructed huge ramparts and moats around it. The city derived its name from the title of Prithviraj Chauhan himself and thus came to be known as Qila Rai Pithora, with Lal Kot as its southwestern base. At present the ruins of Qila Rai Pithora have been conserved in a 20-acre DDA Conservation Park at Mehrauli. The park has an 18-foot high statue of Prithviraj Chauhan and a library. It is being developed as a tourist destination housing an interesting museum and artefacts belonging to the medieval period.