The Mogao Caves are about 25 km from town and you can get here in several ways: through pre-arranged tour group, taxi, or by bus. The green city bus runs to Mogao for 8 yuan each way. The bus also stops at the train station and stops in front of the Silk Road hotel in Dunhuang.
The Mogao Caves are a UNESCO world heritage site and are a large complex of caves, filled with Buddhist artwork, sculpture, frescoes, and other relics. All together, there are 492 temples here that were built/carved over a period of 1,000 years. It truly is a sight worth seeing.