Aerial photo taken on March 17, 2019 shows visitors touring in Beijing Wild Duck Lake National Wetland Park in Yanqing district of Beijing, capital of China. Beijing Wild Duck Lake National Wetland Park reopened on Friday after the winter break. Beijing has been strengthening wildlife protection efforts in recent years and the types of wild animals and plants have been increasing with the ecological environment improving in the national capital. (Xinhua/Wang Jianhua)