São Paulo (; ; "Saint Paul" in English) is a municipality in the southeast region of Brazil. The metropolis is an alpha global city—as listed by the GaWC—and is the most populous city in Brazil and Americas as well as in the Southern Hemisphere. The municipality is also the largest in the Americas and Earth's 12th largest city proper by population. The city is the capital of the surrounding state of São Paulo, one of 26 constituent states of the republic. It is the most populous and wealthiest city in Brazil. It exerts strong international influences in commerce, finance, arts and entertainment. The name of the city honors the Apostle, Saint Paul of Tarsus. The city's metropolitan area of Greater São Paulo ranks as the most populous in Brazil, the 11th most populous on Earth, and largest Portuguese language-speaking city in the world. 

Having the largest economy by GDP in Latin America and the Southern Hemisphere, the city is home to the São Paulo Stock Exchange. Paulista Avenue is the economic core of São Paulo. The city has the 11th largest GDP in the world, representing alone 10.7% of all Brazilian GDP and 36% of the production of goods and services in the state of São Paulo, being home to 63% of established multinationals in Brazil, and has been responsible for 28% of the national scientific production in 2005. With a GDP of US$477 billions, the Sao Paulo city alone could be ranked 24th globally compared with countries. (2016 Estimates).
Looking at the entire planet, where does Sao Paulo rank in city size, by population?
Earth's 12th largest city proper by population