Karachi is the capital city of the Pakistani province of Sindh. It is the largest city in Pakistan and the 12th largest in the world, with a population of over 20 million. It is situated at the southern tip of the country along the Arabian Sea coast and formerly served as the capital of Pakistan. Ranked as a beta-global city, it is Pakistan's premier industrial and financial centre, with an estimated GDP of over $200 billion (PPP) as of 2021. Karachi is a metropolitan city and is considered Pakistan's most cosmopolitan city, and among the country's most linguistically, ethnically-, and religiously-diverse regions, as well as one of the country's most progressive and socially liberal cities.