It borders Shanxi to the west, Henan to the south, Shandong and Liaoning to the east, and Inner Mongolia to the north; in addition, Hebei entirely surrounds the direct-administered municipalities of Beijing and Tianjin on land.It is also home to five National Famous Historical and Cultural Cities: Handan, Baoding, Chengde, Zhengding and Shanhaiguan.Hebei's economy is based on agriculture and manufacturing; it is China's premier steel producer, which has contributed to serious air pollution.[11][12][13][14] In the Yu Gong, the province is recorded as "Jizhou", lending to its traditional abbreviation of "Ji" (冀).[18] Peking Man, an early pre-historic Homo erectus, lived on the plains of Hebei around 200,000 to 700,000 years ago.During the Spring and Autumn period (722–476 BC), Hebei was under the rule of Yan in the north and Jin in the south.Also during this period, a nomadic people known as Dí invaded the plains of northern China and established Zhongshan in central Hebei.At the end of the Han dynasty, most of Hebei was under the control of warlords Gongsun Zan in the north and Yuan Shao further south.During the late Five Dynasties and Ten Kingdoms period, Lulong was fragmented among several regimes including the short-lived Yan.This territory, called the Sixteen Prefectures of Yanyun, became a weakness in the Chinese defense against the Khitans for the next century because it lay within the Great Wall.When the Manchu Qing dynasty came to power in 1644, they abolished the southern counterpart, and Hebei became known as Zhili or Directly Ruled.During the World War II, Hebei was under the control of the Reorganized National Government of the Republic of China, a puppet state of Imperial Japan.Today, Hebei, along with Beijing and Tianjin municipalities which it includes, make up the Jing-Jin-Ji megalopolis region.With a population of 130 million, it is about six times the size of the New York metropolitan area and is one of the largest megalopolis clusters in China.Excluding manmade reservoirs, the largest lake in Hebei is Baiyangdian, located in Anxin County, Baoding.The politics of Hebei is structured in a dual party-government system like all other governing institutions in mainland China.Hebei's industries include textiles, coal, steel, iron, engineering, chemical production, petroleum, power, ceramics, and food.40% of Hebei's labor force works in the agriculture, forestry, and animal husbandry sectors, with the majority of production from these industries going to Beijing and Tianjin.Hebei's main agricultural products are cereal crops, including wheat, maize, millet, and sorghum.According to surveys conducted in 2007 and 2009, 5.52% of the population believe in and are involved in ancestor veneration, while 3.05% identify as Christian, belonging mostly to the Catholic Church.[55] Although the surveys did not provide specific data for other religions, 90.61% of the population are either nonreligious or are involved in worship of nature deities, Buddhism, Confucianism, Taoism, and folk religious sects.[60] Quyang County, in central Hebei, is noted for Ding ware, a type of Chinese ceramics which includes various vessels such as bowls, plates, vases, and cups, as well as figurines.The donkey burger, originating from the cities of Baoding and Hejian, Cangzhou, is a staple in provincial cuisine and has spread into the two municipalities.The Ming Great Wall crosses the northern part of Hebei, and its eastern end is located on the coast at Shanhaiguan (Shanhai Pass), near Qinhuangdao.Current railway systems for Hebei are also being upgraded and will soon be able to travel at speeds of between 160 and 200 kilometres (99 and 124 mi) per hour.[citation needed] Shijiazhuang's Zhengding Airport is the province's center for air transportation, with domestic and international flights.