Mogao Grottoes, inarguably the greatest treasure-trove of Buddhist art found in a single locality anywhere in the world, comprises numerous temples and shrines containing countless sculptures, murals and manuscripts. Dunhuang, initially only a stopover point - albeit, an important one - on the Silk Road, quickly became a Buddhist learning center, where Buddhist sutras and other Buddhist texts were translated into Mandarin, to be spread from there to other cities throughout China.
The grottoes are carved out of the sandstone cliffs of Mingsha Mountain, and extend some 1600 meters from north to south. These grottoes were constructed over a period of a thousand years, from the 4th to the 14th century CE. The remaining Mogao Grottoes (only a little more than half of them are still intact) contain some 45,000 square meters of mural paintings, and more than 2000 painted sculptures.
Over the next thousand years, which saw the rise and fall of not less than sixteen Imperial dynasties, the work of chiseling out the grottoes and of adorning them continued. The construction of the last grotto was completed during the Yuan (CE 1279-1368) Dynasty.The Mogao Grottoes, in addition to its treasure trove of graphic (murals) and sculptural artwork, also comprises a repository of Buddhist scriptures, the so-called Scripture Cave that was hidden behind a wall until early in the 20th century when a self-appointed caretaker of a number of the grottoes, a certain Taoist abbot by the name of Wang Yuanlu, discovered the hidden cave behind a wall.
The Mogao Grottoes is considered as the preeminent Buddhist grotto site in China, surpassing both the Yungang Grottoes site and the Longmen Grottoes site in cultural-historical significance. Indeed, the fact that the UNESCO World Heritage Committee listed the Mogao site as early as 1987, while the Longmen and the Yungang sites were first listed in 2000 and 2001, respectively, reflects the cultural-historical significance, to all of mankind, of the Mogao Grottoes.To gain a better insight into the role of Dunhuang for the spread of Buddhism in this part of China, one should also read the article that describes another of Dunhuang's famous grottoes, the Western Thousand Buddhas Caves, and to appreciate the unique Tangut Empire (think: Western Xia (CE 1038-1227) Dynasty) contribution to Chinese Buddhism, one should also read the article on yet another of Dunhuang's famous grottoes, the Yulin Grottoes.Though Buddhism made its official debut in China in CE 67, it spread slowly initially, only gaining speed after the collapse of the Han (BCE 206 - CE 220) Dynasty and the beginning of the Three Kingdoms (CE 220-280) period of small-state rivalry.
With the acceleration in Silk Road trade in goods, especially westward, beginning in the 4th century CE, the spread of Buddhism eastward along the Silk Road, and then throughout the rest of China - which can be seen as Silk Road "trade" in ideas - also accelerated.