As part of the BBC World Service's Human Race season, ABC in Australia's Lynne Malcolm explores how Homo sapiens have adapted to changes in their environment, economy and social structures; how health is affected by new environments and lifestyles; and what might happen to the human race in the future?
Is the 'Hollywood Dream' of a city of beautiful, fit, wealthy people anything near the truth for this huge city?
It's a city with a long history of immigrants settling from all over the world.
Lynne Malcolm explores how some of these inhabitants have adapted biologically to their new environment over time, and what the impact is on their health and bodies.
BBC Correspondent, Valeria Perasso, discovers however, that it's not all good news, with obesity on the rise in the city and there are also massive discrepancies in the standards of health, and quality of life amongst its inhabitants.
(Image: a female face surrounded by a distorted DNA autoradiogram. Credit: Science Photo Libr