Photo taken on May 17, 2019 shows tourists walking on a glass bridge at Lingjiangyuan Forest Park of Pan'an County, east China's Zhejiang Province. (Photo: Xinhua)

Photo taken on May 17, 2019 shows tourists walking on a glass bridge at Lingjiangyuan Forest Park of Pan'an County, east China's Zhejiang Province. (Photo: Xinhua)

Photo taken on May 17, 2019 shows tourists walking on a glass bridge at Lingjiangyuan Forest Park of Pan'an County, east China's Zhejiang Province. (Photo: Xinhua)

Photo taken on May 17, 2019 shows tourists walking on a glass bridge at Lingjiangyuan Forest Park of Pan'an County, east China's Zhejiang Province. (Photo: Xinhua)

Photo taken on May 17, 2019 shows tourists walking on a glass bridge at Lingjiangyuan Forest Park of Pan'an County, east China's Zhejiang Province. (Photo: Xinhua)