Sadly much of the old architecture was lost during the atrocity of the Mao regime, particularly in the large cities where old structures were bulldozed to build the hideous communist (”we must all be equal”) concrete housing blocks. You have to look hard to find the small remaining historic areas in Shanghai. Ironically, most of that old communist residential housing is being torn down to build the new glass structures popping up all over Beijing, Shanghai and other major cities.
I have been to Beijing quite a few times from 1990 to present.
They were poor, but the city had some character. I can only imagine how interesting the city would be if it had been allowed to develop normally, without the Communist influence over the last 65 years
Modern Beijing is completely without character. Communist planners with money to spend were able to realize their sterile vision of a modern shopping mall crossed with freeways.