Tourists pose for a photo at the Huanghuacheng Lakeside Great Wall Reserve in Beijing, capital of China, Mar 29, 2023. (PHOTO / XINHUA)

This aerial photo taken on Mar 29, 2023 shows the Huanghuacheng Lakeside Great Wall Reserve in Beijing, capital of China. (PHOTO / XINHUA)

This aerial photo taken on Mar 28, 2023 shows the Shuiguan Great Wall in Beijing, capital of China. (PHOTO / XINHUA)

This aerial photo taken on March 29, 2023 shows the Huanghuacheng Lakeside Great Wall Reserve in Beijing, capital of China. (PHOTO / XINHUA)

This photo taken on March 29, 2023 shows the Huanghuacheng Lakeside Great Wall in Beijing, capital of China. (PHOTO / XINHUA)

Tourists visit the Huanghuacheng Lakeside Great Wall Reserve in Beijing, capital of China, Mar 29, 2023. (PHOTO / XINHUA)

A train runs amid blooming flowers near the Juyongguan section of the Great Wall in Beijing, capital of China, Mar 23, 2023. (PHOTO / XINHUA)

This aerial photo taken on Mar 29, 2023 shows the Huanghuacheng Lakeside Great Wall Reserve in Beijing, capital of China. (PHOTO / XINHUA)

Tourists visit the Mutianyu section of the Great Wall in Beijing, capital of China, Mar 29, 2023. (PHOTO / XINHUA)

This photo taken on Mar 29, 2023 shows the Huanghuacheng Lakeside Great Wall Reserve in Beijing, capital of China. (PHOTO / XINHUA)

This aerial photo taken on Mar 29, 2023 shows a boat sailing at the foot of the Huanghuacheng Lakeside Great Wall Reserve in Beijing, capital of China. (PHOTO / XINHUA)

This aerial photo taken on Mar 29, 2023 shows the Huanghuacheng Lakeside Great Wall Reserve in Beijing, capital of China. (PHOTO / XINHUA)

This aerial photo taken on Mar 28, 2023 shows the Shuiguan Great Wall in Beijing, capital of China. (PHOTO / XINHUA)

This aerial photo taken on Mar 28, 2023 shows the Shuiguan Great Wall in Beijing, capital of China. (PHOTO / XINHUA)

Tourists visit the Mutianyu section of the Great Wall in Beijing, capital of China, Mar 29, 2023. (PHOTO / XINHUA)