Karachi ) is the largest city, main seaport and the main financial centre of Pakistan, and the capital of the province of Sindh. With an estimated population between 13 million and 15 million, Karachi is one of the world's largest cities in terms of population and the 10th largest urban agglomeration. It is Pakistan's premier centre of banking, industry, and trade and is home to Pakistan's largest corporations, including those involved in textiles, shipping, automotive industry, entertainment, the arts, fashion, advertising, publishing, software development and medical research. The city is a major hub of higher education in South Asia and the wider Islamic world.Karachi is ranked as a Beta world city. It was the original capital of Pakistan until the construction of Islamabad and is the location of the Port of Karachi and Port Bin Qasim, two of the region's largest and busiest ports. After the independence of Pakistan, the city population increased dramatically when hundreds of thousands of Urdu-speaking migrants or Muhajirs from India, East Pakistan (later Bangladesh) and other parts of South Asia came to settle in Karachi.The city is spread over 3527 km2 in area, almost four times bigger than Hong Kong. It is locally known as the "City of Lights" ) and "The bride of the cities" ) for its liveliness, and the "City of the Quaid" ), having been the birth and burial place of Quaid-e-Azam (Muhammad Ali Jinnah), the founder of Pakistan, who made the city his home after Pakistan's independence from the British Raj on 14th August 1947.