Tourists visit Shanghai Chenshan Botanical Garden by boat in east China's Shanghai, Oct. 6, 2019. (Xinhua/Zhang Jiansong)

Tourists visit the Shanghai Chenshan Botanical Garden in east China's Shanghai, Oct. 6, 2019. (Xinhua/Zhang Jiansong)

A tourist views sunflowers at Shanghai Chenshan Botanical Garden in east China's Shanghai, Oct. 6, 2019. (Xinhua/Zhang Jiansong)

Tourists participate in an event at Shanghai Chenshan Botanical Garden in east China's Shanghai, Oct. 6, 2019. (Xinhua/Zhang Jiansong)