Hanoi is a dirty, gritty city. There are narrow streets and very few cars, but tons of mopeds all honking loudly. Unlike China, everyone (almost) wears a helmet (it's required by law since last January). The roads are very torn up. There are no tall buildings and the architecture still has a big French influence. There's a big street culture with all kinds of businesses run outside (street food, barber shops, etc.).
During a day with no school, the kids and I went with our close friends to Century Park, the Central Park of Shanghai. It was a great day for biking, boating, and going on some rides.