A monk visits the world's first yak museum, Yak Museum of Tibet, in Lhasa, capital of southwest China's Tibet Autonomous Region, May 18, 2014. Having been domesticated for thousands of years on the Qinghai-Tibet Plateau, the yak is the most important animal to Tibetan families, since it is a source of meat, milk, fiber and fuel for fires. The museum, with exhibitions focusing on the origin and domestication of yaks, and yak-themed artwork, opened on Sunday, which is also the International Museum Day. [Photo/Xinhua/Chogo]