The Beijing Subway is a rapid transit system serving the city of Beijing, China. It is one of the largest and busiest subway systems in the world, with over 20 lines and more than 400 kilometers of track. The subway provides an efficient way for residents and tourists to navigate the city, connecting key areas and attractions. Opened in 1969, the Beijing Subway has undergone significant expansion and modernization. It operates daily from early morning until midnight, with trains running frequently. The system is known for its affordability and accessibility, making it a popular choice for millions of passengers each day.