Aerial photo taken on May 3, 2021 shows a bullet train driving on Hainan Roundabout Railway in Haikou, capital of south China's Hainan Province. Haikou, an important city of China's "Belt and Road" initiative and also a core city for the construction of free trade port in Hainan Province, will greet the first China International Consumer Products Expo. (Xinhua/Yang Guanyu)