The Mogao Caves in Dunhuang, Gansu province, located at a choke point along the ancient Silk Road, is one of the most important troves of Buddhist art in the world, and has witnessed the exchange and dialogue between the civilizations that once traveled along its length. The caves were painted over the course of a millennium, from the 4th century to the Yuan Dynasty (1271-1368). In 1987, the Mogao Caves were inscribed on UNESCO's World Heritage List.

Along with the Yulin Caves in neighboring Guazhou county, the Mogao Caves are renowned for their exquisite murals and painted sculptures. They display a virtuosity and diversity of styles, and reflect the multiple facets of social life in times gone past. However, after more than 1,000 years of erosion as a result of sand and wind, the relics have become damaged to varying degrees. As a restorer, Li Bo spends his days "diagnosing and treating" these precious murals and painted sculptures.