Photo taken on Sept. 14, 2018 shows autumn scenery of the Tianchi Lake in Arxan, north China's Inner Mongolia Autonomous Region. (Xinhua/Ren Junchuan)

Photo taken on Sept. 14, 2018 shows autumn scenery of the Tianchi Lake in Arxan, north China's Inner Mongolia Autonomous Region. (Xinhua/Ren Junchuan)

Photo taken on Sept. 14, 2018 shows autumn scenery of the Tianchi Lake in Arxan, north China's Inner Mongolia Autonomous Region. (Xinhua/Ren Junchuan)

Photo taken on Sept. 15, 2018 shows autumn scenery of forest in Arxan, north China's Inner Mongolia Autonomous Region. (Xinhua/Ren Junchuan)

Photo taken on Sept. 14, 2018 shows autumn scenery of the Wusulangzi Lake in Arxan, north China's Inner Mongolia Autonomous Region. (Xinhua/Ren Junchuan)

Photo taken on Sept. 15, 2018 shows autumn scenery of forest in Arxan, north China's Inner Mongolia Autonomous Region. (Xinhua/Ren Junchuan)

Photo taken on Sept. 14, 2018 shows autumn scenery of the Budong River in Arxan, north China's Inner Mongolia Autonomous Region. (Xinhua/Ren Junchuan)

Tourists visit a scenic spot in Arxan, north China's Inner Mongolia Autonomous Region, Sept. 14, 2018. (Xinhua/Ren Junchuan)