BIG CITIES I'D NEVER HEARD OF

For reference, the Bay Area has about 7.3 mm people (if you include Oakland and San Jose - about the same as Hong Kong or Madras). Seattle has about 3.7 mm (about the same as Milan or Barcelona). Here are cities in between I'd never heard of, found here.

Belo Horizonte, Brazil - 5.3 mm
Wuhan, China - 4.8 mm
Harbin, China - 4.6 mm
Shenyang, China - 4.5 mm
Poona, India - 4.3 mm
Abidjan, Ivory Coast - 4.1 mm
Porto Alegre, Brazil - 4.0 mm

And by the way, freakin' Kinshasa now has 7 mm people!