In what year was the first subway in Beijing built?

Beijing’s first subway was built in 1969. This is a 21.2-kilometer subway line connecting downtown Beijing and Beijing West Railway Station. This subway line used light rail trains because the technology at the time was not sufficient to support more advanced subway systems. With the development of Beijing's city and the advancement of technology, the subway system has been continuously improved and expanded. Currently, Beijing's subway system has become one of the largest subway systems in the world, with more than 20 subway lines and more than 400 stations.