Another option which I haven't seen mentioned is the Urban Planning museum. Yep - Urban Planning. This was recommended to me by someone that I met in the lounge last night, but it was the surprise highlight of my day (OK - Jingshan park was nicer, but that I expected to be nice!). The scale models of the city which span most of an entire floor are truly incredible. The people there are all looking to see where they live and how they got here. There was almost nobody there (and certainly no foreigners or tour groups) but everyone was super-engaged in all of the exhibits.

It is located just SE of Tienanmen square, but if you only had an hour I would pick this museum over the other sites that I saw today.

Dr. PITUK