Descendants of Zhang Qian offer incense on the ceremony in memory of Zhang Qian, in Chenggu County, northwest China's Shaanxi Province, April 3, 2018. Zhang Qian, a royal emissary in China's Han Dynasty (202 B.C.-220 A.D.), traveled westward on a mission of peace and opened an overland route linking the East and the West, a daring undertaking which came to be known as Zhang Qian's journey to the Western regions. (Xinhua/Tao Ming)