Project 816 Underground Nuclear Engineering Site

Located in Baitao Street, Fuling District of Chongqing, Project 816 was a top-secret nuclear raw material base approved in 1966 under the Third Front Construction strategy, built by over 60,000 builders for 18 years before suspension in 1984 due to national strategic adjustments. Recognized as the world’s largest artificial mountain hollowed cave complex, it covers a total excavation area of 104,000 square meters with a total tunnel length over 20 kilometers, containing 18 giant caverns and more than 130 branch tunnels, shafts and passages. The core 101 reactor hall stands 79.6 meters tall, equivalent to a 26-story building, with crisscross industrial pipelines, intact central control consoles and giant reactor cavities preserved completely. Two themed exhibition halls display stories of the Two Bombs, One Satellite pioneers and China’s nuclear industry evolution. Constant 18°C temperature inside the mountain, this site combines shocking industrial architecture, precious cold-war national defense heritage and patriotic education value, known as the "Underground Great Wall" of southwest China.