The oasis town of Dunhuang lay at a crucial junction of the Silk Road, that ancient braid of caravan trails stretching for more than 7,000 kilometers from China to the Mediterranean, which served as a highway not just for merchandise, but also for ideas - religious, cultural and artistic. By the 4th century AD, the Silk Road had brought Dunhuang both commercial prosperity and a growing Buddhist community. Some 25 kilometers to its south-east, at the edge of the MingshaShan or Dunes of the Singing Sands, lay a river bed bordered by a long cliff. It was here, in the year 366 AD, that a local monk set about carving out a cave for solitary meditation. Over the next thousand years, hundreds of similar caves were cut into the same rock face - to become not bare monastic cells but richly endowed and adorned shrines. The site began to decline in the 12th century, and slipped into virtual obscurity until the early years of the 20th century. Some 492 decorated caves remain to this day.