Aerial photo taken on April 15, 2021 shows the Garden Expo Park in Jiangning District of Nanjing, east China's Jiangsu Province. The 11th Horticultural Exposition of Jiangsu Province opened in Jiangning, Nanjing, on Thursday. Jiangsu Garden Expo Park is built on abandoned mine pits. Through the revitalization of industrial remains, the once abandoned mine has become an urban oasis where man and nature coexist harmoniously. Photo: Xinhua

Aerial photo taken on April 15, 2021 shows the Garden Expo Park in Jiangning District of Nanjing, east China's Jiangsu Province. The 11th Horticultural Exposition of Jiangsu Province opened in Jiangning, Nanjing, on Thursday. Jiangsu Garden Expo Park is built on abandoned mine pits. Through the revitalization of industrial remains, the once abandoned mine has become an urban oasis where man and nature coexist harmoniously. Photo: Xinhua

A performer plays Guzheng at the Garden Expo Park in Jiangning District of Nanjing, east China's Jiangsu Province, April 15, 2021. The 11th Horticultural Exposition of Jiangsu Province opened in Jiangning, Nanjing, on Thursday. Jiangsu Garden Expo Park is built on abandoned mine pits. Through the revitalization of industrial remains, the once abandoned mine has become an urban oasis where man and nature coexist harmoniously. Photo: Xinhua

Aerial photo taken on April 16, 2021 shows the Garden Expo Park in Jiangning District of Nanjing, east China's Jiangsu Province. The 11th Horticultural Exposition of Jiangsu Province opened in Jiangning, Nanjing, on Thursday. Jiangsu Garden Expo Park is built on abandoned mine pits. Through the revitalization of industrial remains, the once abandoned mine has become an urban oasis where man and nature coexist harmoniously. Photo: Xinhua