Tourists take photos near the Sapukonglagabo Mountain in Biru County of Nagqu, southwest China's Tibet Autonomous Region, May 4, 2021. (Photos: Xinhua)

Photo taken on May 4, 2021 shows a view of the Sapukonglagabo Mountain in Biru County of Nagqu, southwest China's Tibet Autonomous Region.

Photo taken on May 4, 2021 shows a view of the Sapukonglagabo Mountain in Biru County of Nagqu, southwest China's Tibet Autonomous Region.

Photo taken on May 4, 2021 shows a view of the Sapukonglagabo Mountain in Biru County of Nagqu, southwest China's Tibet Autonomous Region.

Birds fly around the Sapukonglagabo Mountain in Biru County of Nagqu, southwest China's Tibet Autonomous Region, May 4, 2021.

Aerial photo taken on May 4, 2021 shows a view of the Sapukonglagabo Mountain in Biru County of Nagqu, southwest China's Tibet Autonomous Region.

Photo taken on May 4, 2021 shows a view of the Sapukonglagabo Mountain in Biru County of Nagqu, southwest China's Tibet Autonomous Region.

Photo taken on May 4, 2021 shows a view of the Sapukonglagabo Mountain in Biru County of Nagqu, southwest China's Tibet Autonomous Region.