Wu Zhuan adjusts his helmet before diving in Changsha, capital of central China's Hunan Province, Jan. 11, 2019. The 30-year-old frogman reinforces an underwater part of a flood protection dike stretching from the Dufu Pavilion by the Xiangjiang River in Changsha to the Yinpenling Bridge on the Xiangjiang River. Every time, Wu Zhuan works underwater with diving devices weighing over 25 kilograms for about three hours. (Xinhua/Xue Yuge)