Children take part in a balance bike contest at a park in Gu'an County, north China's Hebei Province, June 16, 2018. More than 300 children from Beijing, Tianjin and Hebei participated in the activity on Saturday. (Xinhua/Men Congshuo)

A child competes during a balance bike contest at a park in Gu'an County, north China's Hebei Province, June 16, 2018. More than 300 children from Beijing, Tianjin and Hebei participated in the activity on Saturday. (Xinhua/Men Congshuo)

Children take part in a balance bike contest at a park in Gu'an County, north China's Hebei Province, June 16, 2018. More than 300 children from Beijing, Tianjin and Hebei participated in the activity on Saturday. (Xinhua/Men Congshuo)