The red fort complex or lal qila complex in delhi was built by mughal king shahjahan in mid 17 th century. Enclosed within the massive red sand stone walls which stands 75 feet high punctuated by turrets and bastions is a complex of palaces , entertainment halls , projecting balconies , baths indoor canals , geometrical gardens as well as an ornate mosque . Among the most famous structures of the complex are the hall of public audience ( diwan -i- am ) which has 60 red sandstone pillars supporting a flat roof and hall of private audience ( diwan – I- khas ) which is smaller with a pavilion of white marble. The planing of the palace is based on islamic prototypes but each pavilion demonstrates architectural elements typical of mughal building reflecting a fusion of persian , timurid , and hindu tradition. Spread over 255 acres this whole complex was designated as UNESCO World Heritage site in 2007 .