A visitor takes photos of exhibits through a window at the Macao Museum in south China's Macao, Dec. 10, 2014. Macao, covering a total area of more than 30 square kilometers, has more than 20 museums, which is a "very high" density in the world, according to Ung Vai Meng, president of the Cultural Affairs Bureau of Macao Special Administrative Region. [Photo by Li Xin/Xinhua]