Situated in the Xicheng District, Beijing Zoo was the first of its kind to be opened in China. The zoo contains a diverse collection of animals, a number of exhibition halls and some sites of historical interest. The zoo is home to around 900 different species and has a population of some 20,000 animals. Some of the most popular attractions among visitors are the wild and rare animals of China itself, such as the pandas, golden monkeys, milu deer and northeast tigers. However, the collection is far from restricted to those species found only in the People's Republic of China; the polar bears, American bison, zebras, kangaroos, giraffes and elephants also draw large crowds. The Beijing Zoo site is comprised of 16 different exhibition areas and halls. One of the most popular of these is the Panda Hall. Built in 1989 and covering an area of around 10,000 square meters (2.5 acres), it delivers an impressive aesthetic scene while also managing to account for the practical considerations of housing such large and physical animals. The inside of the hall replicates the style of traditional Chinese gardens and is shaped in the pattern of a Tai Chi diagram. Another of the zoo's famous halls, the Gorilla Hall, was constructed two years earlier in 1987. The building houses a series of artificial hillocks and wooden apparatus for the animals which sit against a backdrop of attractive gorilla murals. Facilities introduced for the gorillas include a medical room, a mating room and a specialist feeding room. The hall itself is decorated by a series of rockeries and pools. All of the zoo's halls and exhibition areas are constructed so as to ensure that the animals enjoy a both comfortable and healthy living environment. The Beijing Aquarium is a must for anyone visiting the zoo. Opened in 1999, it is widely-recognized by tourist bodies as being one of the country's top attractions, and is actually the largest inland aquarium in the world. The aquarium features thousands of different aquatic species - man-eating fishes, precious Chinese sturgeons, huge sea elephants and fierce sharks are among some of the highlights. Tourists can also enjoy shows performed by the dolphins, sea lions and whales in the aquarium's Ocean Theater. While at the zoo, visitors also have the chance to sample some the nearby historical relics: Lemarck Hall was built to commemorate the life of Lemarck (1744-1829), a famous French natural historian, and has also been used as the Chinese Botanical Science Research Base. Also on the site is the Song Jiaoren Memorial Tower. Song (1882-1913) was one of the early leaders of the Kuomintang, but was assassinated soon after he was elected as China's premier in 1913. Another site of historical interest is the Changguanlou: a two storied, baroque-style building constructed from brick and wood. In the late-19th century it was occupied by Ci Xi (1835-1908), the Empress Dowager and ruler of the Qing court between 1861 and 1908. Sun Yat-sen (1866-1925), the founder of the Kuomintang, is also said to have lived in the hall during his stay in Beijing. With the support of the Chinese government and having undergone continual development throughout its 90-year history, Beijing Zoo has become one of the largest in China. It provides thousands with the opportunity to witness strange and exotic species at firsthand, and also allows visitors to learn more about the lives of the animals that inhabit the world alongside us.