Wang Tianchang and his son Wang Yinji trim trees in Hongshui Village of Changcheng Township of Wuwei City, northwest China's Gansu Province, Nov. 22, 2016. In the 1990s, Wang Tianchang found that the sand was advancing on the farmland while he was herding on the southwestern edge of Tengger desert. To defend the village, Wang determined to fight against desertification. In 1999, Wang and his son, Wang Yinji, moved to live in the desert. They sold out livestock and even borrowed some money to buy and plant seedlings. After years' of efforts, they have planted 7500 mu (500 hectares) of trees. The father and son's determination attracts public attention. They obtain necessary donation from the society and support from the local authorities to continue their work. (Photo: China News Service/Yang Yanmin)