Perched upon Marpo Ri hill, 130 meters above the Lhasa valley, the Potala Palace rises a further 170 meters and is one of the greatest monumental structure around the world. The palace was built in the seventh century by King Songtsan Gambo, unifier of Tibet, for his bride, the Han nationality Princess Wen Cheng, who was sent to him by the Tang dynasty emperor. Potala Palace occupies an area of 41 hectares, with the 13-storied main building rising 115 meters high. The complex is of stone and wood structure. The upper structure of the place is of wood. The roofs of the main buildings are in traditional Han architectural style with upturned eaves, tinkling bells at each corner and gilded yellow tiles.