Karachi is the largest city in Pakistan and the twelfth-largest city in the world. It is the capital of the Pakistani province of Sindh. Ranked as a beta-global city, it is Pakistan's premier industrial and financial centre, with an estimated GDP of $164 billion as of 2019. Karachi is Pakistan's most cosmopolitan city, linguistically, ethnically, and religiously diverse, as well as one of Pakistan's most secular and socially liberal cities. With its location on the Arabian Sea, Karachi serves as a transport hub, and is home to Pakistan's two largest seaports, the Port of Karachi and Port Bin Qasim, as well as Pakistan's busiest airport, the Jinnah International Airport.
Though the region surrounding and in Karachi has been inhabited for millennia, the city was formally founded as the fortified village of Kolachi in 1729. The settlement drastically increased in importance with the arrival of the British East India Company in the mid-19th century. The British administrations embarked on major projects to transform the city into a major seaport, and connected it with their extensive railway network throughout the Indian subcontinent.