A tour guide speaks during a live streaming tour in the Potala Palace, a UNESCO world heritage, in Lhasa, southwest China's Tibet Autonomous Region, March 1, 2020. The Potala Palace, a landmark in southwest China's Tibet Autonomous Region, held a live streaming tour session Sunday, the first time in its over 1,300-year history. (Xinhua/Jigme Dorje)

A tour guide speaks during a live streaming tour in the Potala Palace, a UNESCO world heritage, in Lhasa, southwest China's Tibet Autonomous Region, March 1, 2020. The Potala Palace, a landmark in southwest China's Tibet Autonomous Region, held a live streaming tour session Sunday, the first time in its over 1,300-year history. (Xinhua/Chun La)

A tour guide speaks during a live streaming tour in the Potala Palace, a UNESCO world heritage, in Lhasa, southwest China's Tibet Autonomous Region, March 1, 2020. The Potala Palace, a landmark in southwest China's Tibet Autonomous Region, held a live streaming tour session Sunday, the first time in its over 1,300-year history. (Xinhua/Chun La)

A tour guide shows the live streaming tour to the Potala Palace, a UNESCO world heritage, in Lhasa, southwest China's Tibet Autonomous Region, March 1, 2020. The Potala Palace, a landmark in southwest China's Tibet Autonomous Region, held a live streaming tour session Sunday, the first time in its over 1,300-year history. (Xinhua/Jigme Dorje)