The Swedish pop band ABBA wins the Eurovision Song Contest with the song "Waterloo", launching their international career.

The Eurovision Song Contest 1974 was the 19th edition of the annual Eurovision Song Contest. It took place in Brighton, United Kingdom and was organized by the European Broadcasting Union (EBU) and host broadcaster British Broadcasting Corporation (BBC), who agreed to host the event after Luxembourg, having won in both 1972 and 1973, declined to host it for a second successive year on the grounds of expense. The contest was held at the Brighton Dome on Saturday 6 April 1974 and was hosted by Katie Boyle for the fourth and final time (having hosted the 1960, 1963 and 1968 editions).

Seventeen countries took part in the contest, with France being absent and Greece competing for the first time this year.

The winner was Sweden with the song "Waterloo" famously performed by the Swedish group ABBA, who would later go on to become one of the best-selling acts in pop music history.

ABBA ( AB-ə, Swedish: [ˈâbːa], formerly named Björn & Benny, Agnetha & Frida) are a Swedish pop group formed in Stockholm in 1972 by Agnetha Fältskog, Björn Ulvaeus, Benny Andersson, and Anni-Frid Lyngstad. The group's name is an acronym of the first letters of their first names arranged as a palindrome. One of the most popular and successful musical groups of all time, they became one of the best-selling music acts in the history of popular music, topping the charts worldwide from 1974 to 1983, and in 2021.

In 1974, ABBA were Sweden's first winner of the Eurovision Song Contest with the song "Waterloo", which in 2005 was chosen as the best song in the competition's history as part of the 50th anniversary celebration of the contest. During the band's main active years, it consisted of two married couples: Fältskog and Ulvaeus, and Lyngstad and Andersson. With the increase of their popularity, their personal lives suffered, which eventually resulted in the collapse of both marriages. The relationship changes were reflected in the group's music, with latter compositions featuring darker and more introspective lyrics. After ABBA separated in December 1982, Andersson and Ulvaeus continued their success writing music for multiple audiences including stage, musicals and movies, while Fältskog and Lyngstad pursued solo careers.Ten years after the group broke up, a compilation, ABBA Gold, was released, becoming a worldwide best-seller. In 1999, ABBA's music was adapted into Mamma Mia!, a successful musical that toured worldwide and, as of November 2021, is still in the top-ten longest running productions on both Broadway (closed in 2015) and the West End (still running). A film of the same name, released in 2008, became the highest-grossing film in the United Kingdom that year. A sequel, Mamma Mia! Here We Go Again, was released in 2018.

In 2016, the group reunited and started working on a digital avatar concert tour. Newly recorded songs were announced in 2018. Voyage, their first new album in 40 years, was released on November 5, 2021. ABBA Voyage, a concert residency featuring ABBA as virtual avatars – dubbed 'ABBAtars' – is due to take place in London from May to December 2022.ABBA is one of the best-selling music artists of all time, with record sales estimated to be between 150 million to 385 million sold worldwide and the group were ranked 3rd best-selling singles artists in the United Kingdom with a total of 11.3 million singles sold by 3 November 2012. ABBA were the first group from a non-English-speaking country to achieve consistent success in the charts of English-speaking countries, including the United States, United Kingdom, Republic of Ireland, Canada, Australia, New Zealand and South Africa. They are the best-selling Swedish band of all time and the best-selling band originating in continental Europe. ABBA had eight consecutive number-one albums in the UK. The group also enjoyed significant success in Latin America and recorded a collection of their hit songs in Spanish. ABBA were inducted into the Vocal Group Hall of Fame in 2002. The group were inducted into the Rock and Roll Hall of Fame in 2010, the first and only recording artists to receive this honour from outside an Anglophone country. In 2015, their song "Dancing Queen" was inducted into the Recording Academy's Grammy Hall of Fame.