People visit the Yinghua Lake in Rongcheng City, east China's Shandong Province, May 27, 2019. Thanks to the ecological protection, the Yinghua lake has been converted from a polluted lake to a theme park. (Xinhua/Li Ziheng)

People visit the Yinghua Lake in Rongcheng City, east China's Shandong Province, May 27, 2019. Thanks to the ecological protection, the Yinghua lake has been converted from a polluted lake to a theme park. (Xinhua/Li Ziheng)

A visitor poses for a photo near the Yinghua Lake in Rongcheng City, east China's Shandong Province, May 27, 2019. Thanks to the ecological protection, the Yinghua lake has been converted from a polluted lake to a theme park. (Xinhua/Li Ziheng)

Visitors pose for a photo near the Yinghua Lake in Rongcheng City, east China's Shandong Province, May 27, 2019. Thanks to the ecological protection, the Yinghua lake has been converted from a polluted lake to a theme park. (Xinhua/Li Ziheng)

People visit the Yinghua Lake in Rongcheng City, east China's Shandong Province, May 27, 2019. Thanks to the ecological protection, the Yinghua lake has been converted from a polluted lake to a theme park. (Xinhua/Li Ziheng)

Photo taken on May 27, 2019 shows scenery in the Yinghua Lake in Rongcheng City, east China's Shandong Province. Thanks to the ecological protection, the Yinghua lake has been converted from a polluted lake to a theme park. (Xinhua/Li Ziheng)