Visitors admire the scenery of twilight shining through the Seventeen Arch Bridge in the Summer Palace in Beijing, capital of China, Dec. 6, 2017. (Xinhua/Ma Zhihong)

Visitors admire the scenery of twilight shining through the Seventeen Arch Bridge in the Summer Palace in Beijing, capital of China, Dec. 6, 2017. (Xinhua/Ma Zhihong)

Visitors admire the scenery of twilight shining through the Seventeen Arch Bridge in the Summer Palace in Beijing, capital of China, Dec. 6, 2017. (Xinhua/Ma Zhihong)