Tibetan architecture is deeply influenced by Buddhism and adapted to local climate, economic activities, and traditions. The architectural forms of structure are varied according to different areas. In Lhasa and Tsang region, the mixed structure of earth, stone and wood is mainly prevalent. In the forested region, such as Nyingchi and Qamdo, wooden or semi-wooden construction is popular. In Ngari, due to the high elevation of above 5,000 meters, adobe is mostly used as material because wood and masonry are relatively in shortage. In northern Tibet, such as Nagqu Prefecture, there are vast lands of pastures. So many people are living a nomad life style. They usually live in tents which are made of yak fur to keep warm and easy to fold and move. In order to get enough heat, houses are normally built facing the south and situated on elevated areas. There are multiple windows on the wall to let the sunshine in and they are relatively small. The visual impression of Tibetan architecture is stable and solemn due to the influence of Buddhism. As to colors, they typically use white and red on the wall, black around windows. For monasteries, red and yellow is widely used because red means guardian and yellow means detached from the secular. Religious architecture represents a high level of artistic value, such as world-famous Potala Palace, Jokhang Temple, Drepung Temple, Samye Temple, Sera Temple and etc.