The WATERLOO Pop Group was a Swedish pop group formed in 1972, best known for their hit single 'WATERLOO'. The group consisted of four members: Agnetha Fältskog, Björn Ulvaeus, Benny Andersson, and Anni-Frid Lyngstad, collectively known as ABBA. ABBA was one of the most successful musical groups of the 1970s, selling over 380 million records worldwide. They won the 1974 Eurovision Song Contest with 'WATERLOO' and went on to become one of the best-selling music artists of all time.