The SOS Pop Group is the Swedish band ABBA, which was formed in 1972 and is one of the most successful pop groups of all time. The group consists of Benny Andersson, Björn Ulvaeus, Agnetha Fältskog, and Anni-Frid Lyngstad. They are best known for their hit songs such as 'Dancing Queen, ' 'Mamma Mia, ' and 'Take a Chance on Me.' ABBA has sold over 380 million records worldwide and is one of the best-selling music artists of all time.