The upper part (file) of this combo photo taken by Chen Xiaobo shows passengers passing the Luohu Port in Shenzhen, south China's Guangdong Province. The lower part of the combo photo taken by Mao Siqian on April 6, 2018 shows a robot at Shenzhen Bay port. This year marks the 40th anniversary of China's reform and opening-up policy. Over the past four decades, Shenzhen has developed from a small fishing village to a metropolis. (Xinhua)