Shenzhen (Shen Zhen; ; Chinese: 深圳; pinyin: Shēnzhèn; Mandarin pronunciation: [ʂə́n.ʈʂə̂n] ) is China's third most economically and technically developed city after Shanghai and Beijing. The city is a Chinese Special Economic zone, a tech hub, and a popular travel destination on the banks of the Pearl River estuary in Guangdong province, bordering Hong Kong to the south. Due to the city's wide renown as a leading global technology hub, Shenzhen is commonly known as China's Silicon Valley. Shenzhen is the headquarter of several largest technology corporations such as electronic hardware company Huawei, telecommunication giant Tencent, and drone researching and manufactoring company DJI. Shenzhen also sub-headquarters Bytedance (Tiktok's parent company) and PDD Inc. (Temu's major collaborator). The city's entrepreneurial, innovative, and competitive-based culture has resulted in the city being home to more numerous small-time manufacturers or software companies over time. As an important international city, Shenzhen hosts numerous national and international events every year, such as the 2011 Summer Universiade and the China Hi-Tech Fair. Shenzhen's rapid success has resulted in the Chinese government turning Shenzhen into a model city for other cities in China to follow. With a population of 17.56 million in 2020, Shenzhen is the third most populous city by urban population in China after Shanghai and Beijing. Shenzhen is a global center in technology, research, manufacturing, business and economics, finance, tourism and transportation, and the Port of Shenzhen is the world's fourth busiest container port. According to statistics, there are as many as 1.152 million foreigners living in Shenzhen, and there are more than 30,000 permanent foreigners.Shenzhen's nominal GDP has surpassed that of its neighbor Hong Kong, and Seattle, Mumbai and Sydney internationally, and it is now among the cities with the ten largest economies in the world. Shenzhen also has the eighth most competitive and largest financial center in the world, the seventh-most Fortune Global 500 headquarters of any city in the world, fifth-highest number of billionaires of any city in the world, the second largest number of skyscrapers of any city in the world, the 28th largest scientific research output of any city in the world, and several notable educational institutions, such as Shenzhen University (ranked #47 in Best Global Universities in Asia), Southern University of Science and Technology, and Shenzhen Technology University. In the early 1980s, economic reforms introduced by Deng Xiaoping resulted in the city becoming the first special economic zone of China due to its close proximity to Hong Kong, attracting foreign direct investment and migrants searching for opportunities. In thirty years, the city's economy and population boomed and has since emerged as a hub for technology, international trade, and finance. It is the home to the Shenzhen Stock Exchange, one of the largest stock exchanges in the world by market capitalization and the Guangdong Free-Trade Zone. Shenzhen is ranked as an Alpha- (global first-tier) city by the Globalization and World Cities Research Network.