Berlin's U7 line has a total of 40 stops and is 31,8 km long. The line starts in Spandau, passes under Neukölln and ends in Rudow.
The U7 line was originally a sideline of the current U6 line and provided traffic between Seestraße and Grenzallee. In 1966, the U7 line left the U6 line and the following years were always extended. Today, the U7 line is Berlin's longest subway line, considering line length, number of stops and driving time. The U7 line was once the longest tunnel in the world because this line passed under the ground.