Perched on top of Hongshan Mountain in the center of Lhasa, the capital of Tibet Autonomous Region, 3,600 meters above sea level, Potala Palace was first built in 641 by Tibetan King Songtsen Gampo to greet his bride Princess Wencheng of the Tang Dynasty (618-907). It then became the chief residence of the Dalai Lama after it was reconstructed by the Fifth Dalai Lama between 1645 and 1693. [Photo by Zheng Yongbo / China.org.cn]