Ballspielverein Borussia 09 e.V. Dortmund, commonly known as Borussia Dortmund [boˈʁʊsi̯a ˈdɔʁtmʊnt],^[1] Dortmund, or BVB, is a German sports club based in Dortmund, North Rhine-Westphalia. The football team is part of a large membership-based sports club with 100,000 members,^[2] making BVB the third largest sports club by membership in Germany. Dortmund plays in the Bundesliga, the top tier of the German football league system. Dortmund is one of the most successful clubs in German football history.^[3][4]