Shanghai is about Beijing size: approx 15M people. The comparison ends here. The city is a lot more international and vibrant. It is walkable, has nice art deco districts (French Concession), is stuffed with fancy restaurants and bars from all cultures. The Huangpu river splits the older part of the city (the Bund) with the modern one (Pudong). It has its own history (not the same kind of history as Xi'an or Beijing though) and influence from the British, French and Japanese. It was Asia's biggest port at the beginning of the 20th century thanks to trade of opium, silk and tea and was known as the "Whore of Asia"... The Chinese communist party was formed here and the city hosted the "Gang of 4" during the Cultural Revolution. Gang was made of Mao Zedong's last wife Jiang Qing and communist associates and has been charged with a series of crimes during the cultural revolution.
In one word this city has a spirit. And apart from the heavy humidity (average annual 75%) and heat, I find it quite livable.
I met good friend Charlie from Thunderbird, now successfully working in marketing for a petroleum company who invited me to taste some of Shanghai delicacies. Great time catching up.
After a few days of good food, fun and exploration I took the 18h train to Hong Kong.