The Yuyuan Garden is located off the Yuyuan Bazaar. You step from one packed and busy bazaar into a relative sea of calm, which is very nice. The garden has an interesting history, which you can read from the Wiki link, and if you’re old, you get in for half price.
There are various pavilions, pools, paths, carvings and rock formations in the garden, which is walled. Outside the walls you can hear the hustle and bustle of the old town.
There’s one magnificent courtyard with a stage. This is still used for performing opera and similar entertainment.