Students of a primary school make dumplings for sanitation workers to greet the upcoming Winter Solstice festival in Zhangjiakou, north China's Hebei Province, Dec. 21, 2017. Winter Solstice, the shortest day of the year, falls on Dec. 22 this year. In Chinese culture, it marks the beginning of deep winter and a break from farming in traditional agricultural society.(Xinhua/wangxiao)