Shanghai is the largest city in China in terms of population and one of the largest metropolitan areas in the world, with over 20 million people. Located on China's central eastern coast at the mouth of the Yangtze River, the city is administered as a municipality of the People's Republic of China with province-level status.

Originally a fishing and textiles town, Shanghai grew to importance in the 19th century due to its favourable port location and as one of the cities opened to foreign trade by the 1842 Treaty of Nanking. The city flourished as a center of commerce between east and west, and became a multinational hub of finance and business by the 1930s. However, Shanghai's prosperity was interrupted after the 1949 Communist takeover and the subsequent cessation of foreign investment. As a Result of Economic reforms in 1990, intense development and financing in Shanghai has resulted, and in 2005 Shanghai became the world's busiest cargo port.

The city is an emerging tourist destination renowned for its historical landmarks such as the Bund and Xintiandi, its modern and ever-expanding Pudong skyline including the Oriental Pearl Tower, and its new reputation as a cosmopolitan center of culture and design. Today, Shanghai is the largest center of commerce and finance in mainland China, and has been described as the "showpiece" of the world's fastest-growing economy.
During the Song Dynasty (AD 960–1279) Shanghai was upgraded in status from a village (cun) to a market town (zhen) in 1074, and in 1172 a second sea wall was built to stabilize the ocean coastline, supplementing an earlier dike. From the Yuan Dynasty in 1292 until Shanghai officially became a city for the first time in 1297, the area was designated merely as a county (xian) administered by the Songjiang Prefecture (Songjiang Fu).

Two important events helped promote Shanghai's development in the Ming Dynasty. A city wall was built for the first time during in 1554, in order to protect the town from raids by Wokou (Japanese pirates). It measured 10 meters high and 5 kilometers in circumference. During the Wanli reign (1573-1620), Shanghai received an important psychological boost from the erection of a City God Temple (Cheng Huang Miao) in 1602. This honor was usually reserved for places with the status of a city, such as a prefectural capital (fu), and was not normally given to a mere county town (zhen) like Shanghai. The honor was probably a reflection of the town's economic importance, as opposed to its low political status.
During the Qing Dynasty, Shanghai became the most important sea port in the whole Yangtze Delta region. This was a result of two important central government policy changes. First of all, Emperor Kangxi (1662-1723) in 1684 reversed the previous Ming Dynasty prohibition on ocean going vessels, a ban that had been in force since 1525. Secondly, Emperor Yongzheng in 1732 moved the customs office (hai guan) for Jiangsu province from the prefectural capital of Songjiang city to Shanghai, and gave Shanghai exclusive control over customs collections for the foreign trade of all Jiangsu province. As a result of these two critical decisions, Professor Linda Cooke Johnson has concluded that by 1735 Shanghai had become the major trade port for all of the lower Yangzi River region, despite still being at the lowest administrative level in the political hierarchy.

The importance of Shanghai grew radically in the 19th century, as the city's strategic position at the mouth of the Yangtze River made it an ideal location for trade with the West. During the First Opium War in the early 19th century, British forces temporarily held Shanghai. The war ended with the 1842 Treaty of Nanjing, which saw the treaty ports, Shanghai included, opened for international trade. The Treaty of the Bogue signed in 1843, and the Sino-American Treaty of Wangsia signed in 1844 together saw foreign nations achieve extraterritoriality on Chinese soil, the start of the foreign concessions.
1854 saw the first meeting of the Shanghai Municipal Council, created in order to manage the foreign settlements. In 1863, the British settlement, located to the south of Suzhou creek (Huangpu district), and the American settlement, to the north of Suzhou creek (Hongkou district), joined in order to form the International Settlement. The French opted out of the Shanghai Municipal Council, and maintained its own French Concession, located to the south of the International Settlement, which still exists today as a popular attraction. Citizens of many countries and all continents came to Shanghai to live and work during the ensuing decades; those who stayed for long periods — some for generations — called themselves "Shanghailanders". In the 1920s and 1930s, almost 20,000 so-called White Russians and Russian Jews fled the newly-established Soviet Union and took up residence in Shanghai. These Shanghai Russians constituted the second-largest foreign community.

The Sino-Japanese War concluded with the Treaty of Shimonoseki, which saw Japan emerge as an additional foreign power in Shanghai. Japan built the first factories in Shanghai, which were soon copied by other foreign powers to effect the emergence of Shanghai industry. Shanghai was then the most important financial center in the Far East.

Under the Republic of China (1911-1949), Shanghai's political status was finally raised to that of a municipality on July 14, 1927. Although the territory of the foreign concessions was excluded from their control, this new Chinese municipality still covered an area of 828.8 square kilometers, including the modern-day districts of Baoshan, Yangpu, Zhabei, Nanshi, and Pudong. Headed by a Chinese mayor and municipal council, the new city governments first task was to create a new city center in Jiangwan town of Yangpu district, outside the boundaries of the foreign concessions. This new city center was planned to include a public museum, library, sports stadium, and city hall.
The Imperial Japanese Navy Air Service bombed Shanghai on 28 January 1932, nominally in an effort to crush down Chinese student protests of the Manchurian Incident and the subsequent Japanese occupation of northeast China. The Chinese fought back in what was known as the January 28 Incident. The two sides fought to a standstill and a ceasefire was brokered in May. The Battle of Shanghai in 1937 resulted in the occupation of the Chinese administered parts of Shanghai outside of the International Settlement and the French Concession. The International Settlement was occupied by the Japanese on 8 December 1941 and remained occupied until Japan's surrender in 1945. According to historian Zhiliang Su, at least 149 "comfort houses" for sexual slaves were established in Shanghai during the occupation.  On 27 May 1949, the Communist Party of China controlled the People's Liberation Army and took control of Shanghai, which was one of only three former Republic of China (ROC) municipalities not merged into neighbouring provinces over the next decade (the others being Beijing and Tianjin). Shanghai underwent a series of changes in the boundaries of its subdivisions, especially in the next decade. After 1949, most foreign firms moved their offices from Shanghai to Hong Kong, as part of an exodus of foreign investment due to the Communist victory.

During the 1950s and 1960s, Shanghai became an industrial center and center for revolutionary leftism. Yet, even during the most tumultuous times of the Cultural Revolution, Shanghai was able to maintain high economic productivity and relative social stability. In most of the history of the People's Republic of China (PRC), Shanghai has been the largest contributor of tax revenue to the central government compared with other Chinese provinces and municipalities. This came at the cost of severely crippling Shanghai's infrastructure and capital development. Its importance to China's fiscal well-being also denied it economic liberalizations that were started in the far southern provinces such as Guangdong during the mid-1980s. At that time, Guangdong province paid nearly no taxes to the central government, and thus was perceived as fiscally expendable for experimental economic reforms. Shanghai was finally permitted to initiate economic reforms in 1991, starting the huge development still seen today and the birth of Lujiazui in Pudong.

Shanghai has a rich collection of buildings and structures of various architectural styles. The Bund, located by the bank of the Huangpu River, contains a rich collection of early 20th century architecture, ranging in style from neo-classical HSBC Building to the art deco Sassoon House. A number of areas in the former foreign concessions are also well preserved, and despite rampant redevelopment, the old city still retains some buildings of a traditional style, including Yuyuan Garden, a traditional garden in the Jiangnan style. In recent years, a large number of architecturally distinctive, even eccentric, skyscrapers have sprung up throughout Shanghai. Notable examples of contemporary architecture include the Shanghai Museum and Shanghai Grand Theatre in the People's Square precinct. One uniquely Shanghainese cultural element is the shikumen residences, which are two or three-story townhouses, with the front yard protected by a high brick wall. Each residence is connected and arranged in straight alleys, known as a lòngtang, pronounced longdang in Shanghainese. The entrance to each alley is usually surmounted by a stylistic stone arch. The whole resembles terrace houses or townhouses commonly seen in Anglo-American countries, but distinguished by the tall, heavy brick wall in front of each house. The name "shikumen" literally means "stone storage door", referring to the strong gateway to each house.

The shikumen is a cultural blend of elements found in Western architecture with traditional Lower Yangtze (Jiangnan) Chinese architecture and social behavior. All traditional Chinese dwellings had a courtyard, and the shikumen was no exception. Yet, to compromise with its urban nature, it was much smaller and provided an "interior haven" to the commotions in the streets, allowing for raindrops to fall and vegetation to grow freely within a residence. The courtyard also allowed sunlight and adequate ventilation into the rooms.
The city also has some beautiful examples of Soviet neoclassical architecture. These buildings were mostly erected during the period from the founding of the People's Republic in 1949 until the Sino-Soviet Split in the late 1950s. During this decade, large numbers of Soviet experts poured into China to aid the country in the construction of a communist state, some of them were architects. Examples of Soviet neoclassical architecture in Shanghai include what is today the Shanghai International Exhibition Center. Beijing, the nation's capital, displays an even greater array of this particular type of architecture. The Pudong district of Shanghai displays a wide range of supertall skyscrapers. The most prominent examples include the Jin Mao Tower and the taller Shanghai World Financial Center, which at 492 metres tall is the tallest skyscraper in mainland China and ranks second in the world. The distinctive Oriental Pearl Tower, at 468 metres, is located nearby toward downtown Shanghai. Its lower sphere is now available for living quarters, at very high prices. Another tall highrise in the Pudong area of Shanghai is the newly finished Development Tower. It stands at 269 meters.

Also in Pudong, a third supertall skyscraper topping the other Shanghai buildings called the Shanghai Tower is under construction. With a height of 632 metres (2074 feet), the building will have 127 floors upon planned completion in 2014.