is the capital city of the Federal Republic of India. Its ever-growing population of 22 million makes it the sixth most populous city in the world. The city has two distinct parts: Old Delhi and New Delhi. While Old Delhi surrounds on the Red Fort built by Emperor Shah Jahan between 1636 and 1658 (not to be confused with the Red Fort in Agra). New Delhi is the commercial and business hub of Delhi. Delhi was the capital of several empires in ancient India and has preserved many ancient monuments and archaeological sites.