People visit the Kunming Dianchi International Convention & Exhibition Center, a venue of the 15th meeting of the Conference of the Parties to the United Nations Convention on Biological Diversity (COP15), in Kunming, southwest China's Yunnan Province, Oct. 18, 2021. Venues of the COP15 are opened to the public free of charge from Oct. 18 to Nov. 7. (Photo by Liang Zhiqiang/Xinhua)