Tianshi Cave is the religious heart of Qingcheng Mountain — a complex of courtyards, pavilions, and a sacred cave built around the site where Zhang Daoling, the First Celestial Master of Taoism, is said to have cultivated the Way during the Eastern Han Dynasty. First constructed in the Sui Dynasty and substantially rebuilt in the Qing, it remains the headquarters of the Qingcheng branch of the Zhengyi school of Taoism.
The main cave is a natural cavity in the cliff face behind the principal hall, with a carved stone figure of Zhang Daoling inside. The complex stretches across several terraced levels, and the upper courtyard gives views back down the forested valley. About two kilometres uphill from Jianfu Palace, it marks the midpoint of the standard front-mountain route and the point at which most visitors pause longest. The Three Emperors Hall and the Ancestral Masters Hall each contain well-preserved painted murals depicting the Taoist heavenly hierarchy.