A herdsman puts his son on the horseback during the nomadic migration on the Ar Horqin grassland in Chifeng City, north China's Inner Mongolia Autonomous Region, May 31, 2019. Yearly nomadic grazing is still a tradition for people live on the Ar Horqin grassland, where was listed of National Important Agricultural Heritage Systems in 2014. For a long time, herdsmen would decide the route and time of yearly nomadic grazing according to the growth of grassland. (Xinhua/Peng Yuan)