Aerial photo taken on March 21, 2018 shows azalea flowers blooming on Wutong Mountain in Luohu District of Shenzhen, south China's Guangdong Province. Known as a paragon of opening-up and development, Shenzhen in Guangdong Province is one of China's earliest special economic zones. Starting from a small town, it has developed into a key economic hub in the past 40 years. (Xinhua/Mao Siqian)