Xuhui Riverside Green is a huge outdoor space with a decent skatepark that's lit up at night, with basketball courts, a climbing wall, places to run without the fear of cars, and plenty of grass to lay down in. There is also a very crowded dog park. This is more of a place to come play sports or go for a long walk. Also a favorite for public workout communities like FitFam. You've also got two of Shanghai's biggest museums – Long Museum and Yuz Museum. Always free and open 24/7.