Zhazi Cave, located at the foot of Gele Mountain in Chongqing, was a famous site of the Communist Revolution. With mountains on three sides, the location was well-protected. It was once a small coal mine. It was known for a dearth of coal and an abundance of coal slag. In 1938 the Kuomintang rebuilt the mine as a secret prison, where Communist revolutionaries were imprisoned and tortured. One of the most famous martyrs of this prison is Jiang Zhuyun (also known as Sister Jiang). The prison inside Zhazi Cave is divided into an interior section and an exterior section. The interior section includes 16 cells for male inmates and 2 cells for female inmates. The exterior section was used as an office and also had torture rooms.