The Mogao Grottos of China—a UNESCO World Heritage Site—are often referred to as an “art gallery in the desert.” For more than a thousand years, kings, merchants, monks, and nuns called the nearby desert oasis of Dunhuang home. Not far from town they sponsored the excavation and decoration of nearly 500 caves with paintings that depicted Buddhist iconography, local folktales, and life along the Silk Road. Historian Justin M. Jacobs traces the history of the grottos, analyzes the paintings, and discusses the controversial fate of a secret “cave library.”