Shenzhen is a major city in the south of Southern China's Guangdong Province, situated immediately north of Hong Kong Special Administrative Region. The area became China's first—and one of the most successful—Special Economic Zones (SEZs). It currently also holds sub-provincial administrative status, with powers slightly less than a province. According to the 2010 National Census, Shenzhen is the tenth most populous city in mainland China with a population of 10.35 million. Being southern mainland China's major financial center, Shenzhen is home to the Shenzhen Stock Exchange as well as the headquarters of numerous high-tech companies. Shenzhen is now considered one of the fastest-growing cities in the world. It is also one of the busiest container ports in China.