According to the Population Reference Bureau, Shanghai is currently the world’s largest city by population, with almost 14 million residents.

Here’s the list of the top ten largest cities by population:

* Shanghai, China – 13.831 million
* Mumbai, India – 13.830 million
* Karachi, Pakistan – 12.991 million
* Delhi, India – 12.565 million
* Istanbul, Turkey – 11.372 million
* São Paulo, Brazil – 11.037 million
* Moscow, Russia – 10.508 million
* Seoul, South Korea – 10.464 million
* Beijing, China – 10.123 million
* Mexico City, Mexico – 8.841 million

Here’s the list of the top ten largest cities by area:

* Hulunbuir, China – 101,913 Square Miles
* Altamira, Brazil – 61,659 Square Miles
* City of Kalgoorlie-Boulder, Australia – 36,901 Square Miles
* Chongqing, China – 31,815 Square Miles
* Wood Buffalo, Alberta, Canada – 24,456 Square Miles
* Leh, India – 17,417 Square Miles
* City of Mount Isa, Queensland – 17,606 Square Miles
* Porto Velho, Brazil – 13,159 Square Miles
* La Tuque, Quebec, Canada – 11,466 Square Miles
* Yakutat City and Borough, Alaska, United States – 9,459 Square Miles

By 2050, the world population is estimated to surpass the 9 billion mark (9,000,000,000). Urban population (people living in a city) has experienced a tremendous increase over the last century (220 million at the beginning of the century to 2.8 billion at the end). As the population rises this will result in swelling of existing cities and rise in the number of new cities, so this list will change over time.