Beijing contains several well-preserved pagodas and stone pagodas, such as the towering Pagoda of Tianning Temple, which was built during the Liao dynasty from 1100 to 1120, and the Pagoda of Cishou Temple, which was built in 1576 during the Ming dynasty. Historically noteworthy stone bridges include the 12th-century Lugou Bridge, the 17th-century Baliqiao bridge, and the 18th-century Jade Belt Bridge. The Beijing Ancient Observatory displays pre-telescopic spheres dating back to the Ming and Qing dynasties. The Fragrant Hills (''Xiangshan'') is a public park that consists of natural landscaped areas as well as traditional and cultural relics. The Beijing Botanical Garden exhibits over 6,000 species of plants, including a variety of trees, bushes and flowers, and an extensive peony garden. The Taoranting, Longtan, Chaoyang, Haidian, Milu Yuan and Zizhu Yuan parks are some of the notable recreational parks in the city. The Beijing Zoo is a center of zoological research that also contains rare animals from various continents, including the Chinese giant panda.