Photo taken on July 28, 2020 shows an inner view of the iconic "water cube" swimming venue from 2008, which now has become the "ice cube", a premier curling venue, in Beijing, capital of China. (Photos: Xinhua)

Photo taken on July 29, 2020 shows a tree with a QR code in Yanqing, located in the northern suburbs of Beijing, capital of China. In addition to the Olympic Village, all trees in the entire Yanqing competition zone were registered and had their profiles marked with a QR code.

Photo taken on July 28, 2020 shows an inner view of the iconic "Water Cube" swimming venue from 2008, which now has become the "Ice Cube", a premier curling venue, in Beijing, capital of China.

Photo taken on July 28, 2020 shows an inner view of the National Speed Skating Oval, also known as the "Ice Ribbon", in Beijing, capital of China.

Photo taken on July 28, 2020 shows an inner view of the iconic "Water Cube" swimming venue from 2008, which now has become the "Ice Cube", a premier curling venue, in Beijing, capital of China.

Photo taken on July 29, 2020 shows a view of the National Sliding Center in Yanqing, located in the northern suburbs of Beijing, capital of China.

Aerial photo taken on July 30, 2020 shows the construction site of the National Ski Jumping Center in Chongli District of Zhangjiakou City, north China's Hebei Province.

Photo taken on July 28, 2020 shows a view of the National Speed Skating Oval, also known as the "Ice Ribbon", in Beijing, capital of China.

Photo taken on July 28, 2020 shows an inner view of the iconic "Water Cube" swimming venue from 2008, which now has become the "Ice Cube", a premier curling venue, in Beijing, capital of China. (Xinhua/Zhang Chenlin)

Photo taken on July 28, 2020 shows an inner view of the National Speed Skating Oval, also known as the "Ice Ribbon", in Beijing, capital of China.

Aerial photo taken on July 30, 2020 shows Genting Resort in Chongli District of Zhangjiakou City, north China's Hebei Province. Genting Resort will be the site for the Freestyle Skiing and Snowboard competitions in 2022 Winter Olympic Games.

Aerial photo taken on July 30, 2020 shows the construction site of the National Ski Jumping Center in Chongli District of Zhangjiakou City, north China's Hebei Province.

Photo taken on July 29, 2020 shows a view of the National Sliding Center in Yanqing, located in the northern suburbs of Beijing, capital of China.

Aerial photo taken on July 30, 2020 shows the construction site of the National Ski Jumping Center in Chongli District of Zhangjiakou City, north China's Hebei Province.

Photo taken on July 29, 2020 shows a view of the National Sliding Center in Yanqing, located in the northern suburbs of Beijing, capital of China.

Photo taken on July 29, 2020 shows a view of the National Sliding Center in Yanqing, located in the northern suburbs of Beijing, capital of China.