Three tourists take their souvenir photos with the backdrop of Crescent Moon Spring while enjoying the sightseeing of the Singing Sand Dunes, a popular tour resort in the subsurb of Dunhuang City, northwest China's Gansu Province, April 28, 2010. The scenic spots in Dunhuang, a booming town on the ancient Silk Road and the home to more than 800 grottoes at least 1,600 years old, is getting warming up for the tour hightide during the forthcoming 3-days' May 1st Vacation. The frescoes and carvings in the Mogao grottoes at Dunhuang are some of China's best preserved examples of Buddhist art. Photo: Xinhua