Tourists visit Shanhaiguan Pass, a famous tourist resort in Qinhuangdao City, north China's Hebei Province, May 18, 2018. (Xinhua/Liu Chan)

Photo taken by a phone on May 18, 2018 shows Shanhaiguan Pass, a famous tourist resort in Qinhuangdao City, north China's Hebei Province. (Xinhua/Liu Chan)

Tourists visit Shanhaiguan Pass, a famous tourist resort in Qinhuangdao City, north China's Hebei Province, May 18, 2018. (Xinhua/Liu Chan)

Photo taken on May 18, 2018 shows Shanhaiguan Pass, a famous tourist resort in Qinhuangdao City, north China's Hebei Province. (Xinhua/Liu Chan)

Tourists visit Shanhaiguan Pass, a famous tourist resort in Qinhuangdao City, north China's Hebei Province, May 18, 2018. (Xinhua/Liu Chan)