Shanghai is probably the closest China's comes to have a real international city with a cosmopolitan feel to it. It is the largest city with more than 13 millions inhabitants and it is an enchanting mix of old and new architecture. Visit the Bund where foreign powers used to rule from 1842 until mid 1930's and look across the Huangpu river to Pudong. The most virile symbol of modern Shanghai and it's latest succes.
Chinatown was the place where the Chinese lived during the concession period and today it is a buzzing shopping center with the Yu Yuan (garden) as a small oasis right in the middle of it all. Almost everywhere in Shanghai it is just to head down one of the small streets to experience the real life of the Shanghainese. Especially Chinatown has little shops everywhere selling almost everything Chinese. Just leave the renovated center by the garden and you are in the real Chinatown.
Downtown Shanghai is also where the Jade Buddha Temple is at. The temple is home to the extraordinary 2 m high, 1000 kg heavy white jade Buddha, who was imported from Burma some 100 years ago. The temple is an active place of worship for Buddhist from Shanghai and tourists visiting.
The nicest place to stroll around is perhaps in the old concession areas of down town. It is almost impossible to avoid the feeling of beeing transferred back and forth between the past and the present. It is also here you can find many shops and the walking street Nanjing dong and xi lu. Nanjing donglu used to be the best shopping street in Shanghai, but nowadays Nanjing xilu seems more stylish and with a boutique atmosphere instead of donglu's old style shoppingmalls.
Remember that almost no matter where in downtown it is just to turn down one of the alleys, and you'll find the real Shanghai.