ABBA ( AB-ə [ˈâbːa]) were a Swedish pop group formed in Stockholm in 1972 by Agnetha Fältskog, Björn Ulvaeus, Benny Andersson, and Anni-Frid Lyngstad. They are among the most renowned and commercially successful musical groups in history, ranking as one of the best-selling acts in the history of popular music. In 1974, ABBA won the Eurovision Song Contest for Sweden with their song "Waterloo". In 2005, 'Waterloo" was chosen as the best song in the competition's history during its 50th anniversary celebration.
https://en.wikipedia.org/wiki/ABBA