Aerial photo taken on Dec. 24, 2019 shows a 110-kV power transformer substation in Tsonyi County, Nagqu City, southwest China's Tibet Autonomous Region. On May 23, 1951, the Agreement of the Central People's Government and the Local Government of Tibet on Measures for the Peaceful Liberation of Tibet (17-Article Agreement) was signed, officially proclaiming the peaceful liberation of Tibet. The year 2021 marks the 70th anniversary of the historic event. (Xinhua/Sun Fei)
