Aerial photo taken on Dec. 14, 2019 shows a view of the Hukou Waterfall scenic spot. Hukou waterfall is located on the border area between north China's Shanxi and northwest China's Shaanxi provinces. (Photos: Xinhua)

Aerial photo taken on Dec. 14, 2019 shows tourists taking photos at the Hukou Waterfall scenic spot. Hukou waterfall is located on the border area between north China's Shanxi and northwest China's Shaanxi provinces.

Photo taken on Dec. 14, 2019 shows tourists visiting the Hukou Waterfall scenic spot. Hukou waterfall is located on the border area between north China's Shanxi and northwest China's Shaanxi provinces.

Aerial photo taken on Dec. 14, 2019 shows tourists visiting the Hukou Waterfall scenic spot. Hukou waterfall is located on the border area between north China's Shanxi and northwest China's Shaanxi provinces.

Aerial photo taken on Dec. 14, 2019 shows tourists visiting the Hukou Waterfall scenic spot. Hukou waterfall is located on the border area between north China's Shanxi and northwest China's Shaanxi provinces.

Photo taken on Dec. 14, 2019 shows the Hukou Waterfall scenic spot covered in ice. Hukou waterfall is located on the border area between north China's Shanxi and northwest China's Shaanxi provinces.

Aerial photo taken on Dec. 14, 2019 shows tourists visiting the Hukou Waterfall scenic spot. Hukou waterfall is located on the border area between north China's Shanxi and northwest China's Shaanxi provinces.

Aerial photo taken on Dec. 14, 2019 shows tourists visiting the Hukou Waterfall scenic spot. Hukou waterfall is located on the border area between north China's Shanxi and northwest China's Shaanxi provinces.

Aerial photo taken on Dec. 14, 2019 shows tourists visiting the Hukou Waterfall scenic spot. Hukou waterfall is located on the border area between north China's Shanxi and northwest China's Shaanxi provinces.