Shenzhen is a major sub-provincial city on the east bank of the Pearl River estuary on the central coast of southern Guangdong province, People's Republic of China. It forms part of the Pearl River Delta megalopolis, bordering Hong Kong to the south, Huizhou to the northeast and Dongguan to the northwest, and shares maritime boundaries with Guangzhou, Zhongshan and Zhuhai to the west and southwest across the estuary.
Shenzhen's cityscape results from its vibrant economy—made possible by rapid foreign direct investment (FDI) following the institution of the policy of "reform and opening-up" in 1979. Shenzhen roughly follows the administrative boundaries of Bao'an County, officially became a city in 1979, taking its name from the former county town, whose train station was the last stop on the Mainland Chinese section of the railway between Canton and Kowloon. In 1980, Shenzhen was established as China's first special economic zone. The city is a leading global technology hub, dubbed by media China's Silicon Valley. It was one of the fastest-growing cities in the world in the 1990s and the 2000s. Shenzhen's registered population as of 2017 was estimated at 12,905,000, but local police and authorities estimate the real population at about 20 million, due to large populations of short-term residents, unregistered floating migrants, part-time residents, commuters, visitors, as well as other temporary residents.Shenzhen is ranked as an Alpha- (global first-tier) city by the Globalization and World Cities Research Network. In the 2020 Global Financial Centres Index, Shenzhen was ranked as having the 9th most competitive financial center in the world (between San Francisco and Zürich) and 6th most competitive in Asia-Pacific. Shenzhen has the fifth-highest number of billionaires of any city in the world (after Beijing, New York City, Shanghai and Hong Kong). It has the third busiest container port in the world. Shenzhen's high port traffic levels combined with a high urban population make Shenzhen a Large-Port Megacity, the largest type of port-city in the world. Shenzhen has been ranked second on the list "top 10 cities to visit in 2019" by Lonely Planet. The city hosts the Shenzhen Stock Exchange as well as the headquarters of numerous multinational companies such as JXD, Vanke, Hytera, CIMC, SF Express, Shenzhen Airlines, Nepstar, Hasee, Ping An Bank, Ping An Insurance, China Merchants Bank, Evergrande Group, Tencent, ZTE, OnePlus, Huawei, DJI and BYD. Shenzhen is an international hub of research and innovation in China and ranks 32nd globally by scientific research outputs as tracked by the Nature Index. The city is home to several notable institutes, such as Shenzhen University and Southern University of Science and Technology.