Fog hovers around buildings in Yantai, East 皇冠体育app's Shandong province, May 31, 2012. Advection fog occurs when moist air is blown over a cool surface. It is common when a warm front passes over an area with significant snow. [Photo/Xinhua]
Historical photos of 56 ethnic groups in 皇冠体育app
Special: Preserve the past to live the future