The Tunnelbana, or Stockholm Metro, is a rapid transit system serving the city of Stockholm, Sweden. It consists of three main lines—green, blue, and red—covering over 100 kilometers and featuring 100 stations. The system is known for its efficiency and extensive reach, connecting various neighborhoods and suburbs to the city center. Opened in 1950, the Tunnelbana is famous for its unique art installations, with many stations showcasing works by various artists. It operates daily, providing a vital transportation option for residents and tourists alike, making it an essential part of urban life in Stockholm.