Shanghai is the largest city in China, and one of the largest metropolitan areas in the world, with over 20 million people.Located on China's central eastern coast just 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 favorable 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. After 1990, the economic reforms introduced by Deng Xiaoping resulted in intense re-development and financing in Shanghai, and in 2005 Shanghai became the world's largest cargo port. Shanghai will hold the World Expo 2010, the largest event in China since the 2008 Olympics.
The city is a tourist destination renowned for its historical landmarks such as the Bund and City God Temple, 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 major economy.
Shanghai has a humid subtropical climate (Koppen climate classification Cfa) and experiences four distinct seasons. In winter, cold northerly winds from Siberia can cause nighttime temperatures to drop below freezing, although most years there are only one or two days of snowfall. Summer in Shanghai is very warm and humid, with occasional downpours or freak thunderstorms. The city is also susceptible to typhoons, none of which in recent years has caused considerable damage. The most pleasant seasons are Spring, although changeable, and Autumn, which is generally sunny and dry. Shanghai experiences on average 1,878 hours of sunshine per year, with the hottest temperature ever recorded at 40 ¡ãC (104 ¡ãF), and the lowest at ?12 ¡ãC (10.4 ¡ãF). The average number of rainy days is 112 per year, with the wettest month being June. The average frost-free period is 276 days.