People visit the Qianmen Street in Beijing, capital of China, Feb. 9, 2017. Beijing has strengthened the protection of cultural sites in recent years, aimed to improve environment for people's living and travelling. (Xinhua/Li Xin)

Photo taken on Feb. 8, 2017 shows the white pagoda in Beihai Park in Beijing, capital of China. Beijing has strengthened the protection of cultural sites in recent years, aimed to improve environment for people's living and travelling. (Xinhua/Li Xin)

People visit near the Palace Museum in Beijing, capital of China, Feb. 8, 2017. Beijing has strengthened the protection of cultural sites in recent years, aimed to improve environment for people's living and travelling. (Xinhua/Li Xin)

People visit the Qianmen Street in Beijing, capital of China, Feb. 9, 2017. Beijing has strengthened the protection of cultural sites in recent years, aimed to improve environment for people's living and travelling. (Xinhua/Li Xin)

A man takes photos of the Palace Museum at Jingshan Park in Beijing, capital of China, Feb. 8, 2017. Beijing has strengthened the protection of cultural sites in recent years, aimed to improve environment for people's living and travelling. (Xinhua/Li Xin)