Photo taken on April 21, 2020 shows a view of the mountainous area in south Jinan, capital of east China's Shandong Province.

Photo taken on April 21, 2020 shows tourists walking on a bridge in the mountainous area in south Jinan, capital of east China's Shandong Province.

Photo taken on April 21, 2020 shows a view of the mountainous area in south Jinan, capital of east China's Shandong Province.

Photo taken on April 21, 2020 shows tourists admiring the landscape of the mountainous area in south Jinan, capital of east China's Shandong Province.

Photo taken on April 21, 2020 shows tourists walking along a path in the mountainous area in south Jinan, capital of east China's Shandong Province.

Aerial hoto taken on April 21, 2020 shows a view of the mountainous area in south Jinan, capital of east China's Shandong Province.

Photo taken on April 21, 2020 shows a view of the mountainous area in south Jinan, capital of east China's Shandong Province.

Photo taken on April 21, 2020 shows a view of the mountainous area in south Jinan, capital of east China's Shandong Province.

Aerial photo taken on April 21, 2020 shows a view of the mountainous area in south Jinan, capital of east China's Shandong Province. (Photos: Xinhua/Zhu Zheng)