Over 30 kms of hand-dug tunnels to serve as a bomb shelter exists under the city of Beijing, it is known as the Beijing Underground City. It also goes by the name of Underground Great Wall since they share the same purpose of protecting the citizens of the city. Beijing Underground City was constructed during the Sino-Soviet conflict as ordered by Chairman Mao Zedong in fear of nuclear attacks. Over 300,000 people laboured day in and day out to finish the tunnels which included school children. During this time, every household in the city had a trap door which leads to the tunenls. There are several facilities down there which included clinics, schools, restaurants, stores and even a roller skating rink. Tour groups can enter without charge while individual tourists are charged 20 yuan.
