The murals in Dunhuang are also the treasures of world art, with extremely rich contents, which can be roughly divided into nine categories: portrait paintings, historical paintings, story paintings, figure paintings, Buddhist historical relics, architectural fierce paintings, landscape paintings, animal paintings, decorative paintings and so on. Classics, stories and paintings of Buddhist monuments all have very vivid pictures of people's lives. A wide variety of murals reflect the real life of ancient society in many ways, and provide extremely precious image historical materials for the study of China's social history, culture, politics, economy, military, science and technology, religion, architecture, transportation, costumes, music and dance, folk customs and so on. Therefore, it is called "the library on the wall" and a special "museum" internationally, and it is an "image history" spanning thousands of years.