Karachi is the largest and most populous city in Pakistan and 7th most populous urban area in the world. Karachi is the capital of Sindh province of Pakistan, and was the capital of Pakistan until 1958. It is Pakistan's most cosmopolitan city. Situated on the Arabian Sea, Karachi serves as a transport hub, and is home to two of Pakistan's two largest seaports, the Port of Karachi and Port Bin Qasim, as well as the busiest airport in Pakistan.