Charlton Athletic Football Club is an English professional association football club based in Charlton, south-east London. They currently compete in the EFL Championship, the second tier of English football. The club was founded on 10 June 1905. Charlton turned professional in 1920 and first entered the Football League in 1921. Since then the club has had four separate periods in the top flight of English football: 1936–1957, 1986–1990, 1998–1999, and 2000–2007. Historically, Charlton's most successful period was the 1930s, when the club's highest league finishes were recorded, including runners-up of the First Division in 1937. After World War II, Charlton reached two consecutive FA Cup finals, losing in 1946, and winning in 1947.