Delhi’s urban area is now considered to extend beyond the NCT boundaries, and include the neighbouring satellite cities of Ghaziabad, Faridabad, Gurgaon and Noida in an area called the National Capital Region (NCR) and had an estimated 2016 population of over 26 million people, making it the world’s second-largest urban area according to the United Nations. Delhi’s culture has been influenced by its lengthy history and historic association as the capital of India, Although a strong Punjabi Influence can be seen in language, Dress and Cuisine brought by the large number of refugees who came following the partition in 1947 the recent migration from other parts of India has made it a melting pot. This is exemplified by many significant monuments in the city. Delhi is also identified as the location of Indraprastha, the ancient capital of the Pandavas. The Archaeological Survey of India recognises 1,200 heritage buildings and 175 monuments as national heritage sites. In the Old City, the Mughals and the Turkic rulers constructed several architecturally significant buildings, such as the Jama Masjid—India’s largest mosque built in 1656 and the Red Fort. Three World Heritage Sites—the Red Fort, Qutub Minar and Humayun’s Tomb—are located in Delhi. Other monuments include the India Gate, the Jantar Mantar—an 18th-century astronomical observatory—and the Purana Qila—a 16th-century fortress. The Laxminarayan Temple, Akshardham temple, Gurudwara Bangla Sahib, the Baháʼí Faith’s Lotus Temple and the ISKCON temple are examples of modern architecture. Raj Ghat and associated memorials houses memorials of Mahatma Gandhi and other notable personalities. New Delhi houses several government buildings and official residences reminiscent of British colonial architecture, including the Rashtrapati Bhavan, the Secretariat, Rajpath, the Parliament of India and Vijay Chowk. Safdarjung’s Tomb is an example of the Mughal gardens style. Some regal havelis (palatial residences) are in the Old City.