Taiping Heavenly Kingdom Historical Museum

Hong Xiuquan, the Hakka leader of the quasi-Christian Taiping, had a palace built in Nanjing (then named Tianjing or 'Heavenly Capital'), but the building was completely destroyed when Nanjing was bloodily retaken in 1864, after a long siege. This museum is set in a beautiful Ming dynasty garden complex that once housed Taiping officials.
The beautiful Zhan Garden is located inside the museum and ticket price covers both sites.