ABBA were a Swedish pop group formed in Stockholm in 1972 by members Agnetha Fältskog, Björn Ulvaeus, Benny Andersson, and Anni-Frid Lyngstad. They became one of the most commercially successful acts in the history of popular music, topping the charts worldwide from 1974 to 1982. ABBA won the Eurovision Song Contest 1974 at The Dome in Brighton, UK, giving Sweden its first triumph in the contest, and are the most successful group ever to take part in the competition. ABBA's record sales figure is uncertain and various estimates range from over 140 to over 500 million sold records. This makes them one of the best-selling music artists. ABBA was the first group from a non-English-speaking country to achieve consistent success in the charts of English-speaking countries, including the UK, Ireland, Canada, Australia, New Zealand, South Africa, and on a lesser scale, the U.S. The group also enjoyed significant success in Latin American markets, and recorded a collection of their hit songs in Spanish. During the band's active years, Fältskog & Ulvaeus and Lyngstad & Andersson were married. At the height of their popularity, both relationships were suffering strain which ultimately resulted in the collapse of the Ulvaeus–Fältskog marriage in 1979 and the Andersson–Lyngstad marriage in 1981. These relationship changes were reflected in the group's music, with later compositions featuring more introspective and dark lyrics in contrast to their usual pure-pop sound. After ABBA disbanded in December 1982, Andersson and Ulvaeus achieved success writing music for the stage, while Lyngstad and Fältskog pursued solo careers with mixed success. ABBA's music declined in popularity until the purchase of ABBAs catalogue and record company Polar by Polygram in 1989 enabled the groundwork to be laid for an international re-issue of all their original material and a new Greatest Hits (ABBA Gold) collection in the Autumn of 1992 which became a worldwide smash. Several films, notably Muriel's Wedding (1994) and The Adventures of Priscilla, Queen of the Desert (1994), further revived public interest in the group and the spawning of several tribute bands. In 1999, ABBA's music was adapted into the successful musical Mamma Mia! that toured worldwide. A film of the same name, released in 2008, became the highest-grossing film in the United Kingdom that year. ABBA were honoured at the 50th anniversary celebration of the Eurovision Song Contest in 2005, when their hit "Waterloo" was chosen as the best song in the competition's history. The group was inducted into the Rock and Roll Hall of Fame in 2010.In 2015, their song Dancing Queen was inducted into the Recording Academy's Grammy Hall of Fame.