Borussia VfL 1900 Mönchengladbach e.V., commonly known as Borussia Mönchengladbach, Mönchengladbach or Gladbach, is a German football club in Mönchengladbach, North Rhine-Westphalia. Founded in 1900, Borussia Mönchengladbach play in the Bundesliga, the top tier of the German football league system, making their first appearance in the league during the 1965–66 season. Subsequently, the club became one of Germany's best-known, best-supported, and most successful teams, winning the Bundesliga five times during the 1970s. Since 2004, Borussia Mönchengladbach have played at the 54,057 capacity Borussia-Park, having previously played at the smaller Bökelbergstadion since 1919. Borussia-Park is famous for its "Nordkurve", a single-tiered stand. Borussia Mönchengladbach has over 75,000 members as of April 2016 and is the fifth largest club in Germany. Their main rivals are 1. FC Köln, who they compete against in the Rheinland Derby. "Borussia" is a Latinized form of Prussia, a popular term for German clubs in the former Kingdom of Prussia. The club's nickname is Die Fohlen, coined in the 1970s due to having a young team with a fast, aggressive playing style.