Aerial photo taken on June 12, 2017 shows the night view of Mong Kok in Hong Kong, south China. Known as the "Pearl of the Orient", Hong Kong has a land area of more than 1,100 square kilometers. The metropolis boasts not only its well-known architectural landmarks but also beautiful natural landscapes. Various landforms offer habitats for animals and plants in the city. And Hong Kong has put efforts on ecological protection for years to achieve sustainable development. The Beijing International Horticultural Exhibition holds the "Hong Kong Day" event from Sept. 19 to 21. (Xinhua/Lui Siu Wai)