Photo taken on May 18, 2016 shows the grand view of Banchangyu section of the Great Wall in Qinhuangdao City, north China's Hebei Province. (Xinhua)

Photo taken on May 18, 2016 shows the grand view of Banchangyu section of the Great Wall in Qinhuangdao City, north China's Hebei Province. (Xinhua)

Photo taken on May 18, 2016 shows the grand view of Banchangyu section of the Great Wall in Qinhuangdao City, north China's Hebei Province. (Xinhua)

Tourists walk on Banchangyu section of the Great Wall in Qinhuangdao City, north China's Hebei Province on May 18, 2016. (Xinhua)

Photo taken on May 18, 2016 shows the grand view of Banchangyu section of the Great Wall in Qinhuangdao City, north China's Hebei Province. (Xinhua)

Photo taken on May 18, 2016 shows the grand view of Banchangyu section of the Great Wall in Qinhuangdao City, north China's Hebei Province. (Xinhua)

Photo taken on May 18, 2016 shows the grand view of Banchangyu section of the Great Wall in Qinhuangdao City, north China's Hebei Province. (Xinhua)

Photo taken on May 18, 2016 shows the grand view of Banchangyu section of the Great Wall in Qinhuangdao City, north China's Hebei Province. (Xinhua)

Photo taken on May 18, 2016 shows the grand view of Banchangyu section of the Great Wall in Qinhuangdao City, north China's Hebei Province. (Xinhua)

Photo taken on May 18, 2016 shows the grand view of Banchangyu section of the Great Wall in Qinhuangdao City, north China's Hebei Province. (Xinhua)