ABBA forever!

It's been 40 years since Björn Ulvaeus, Agnetha Fältskog, Anni-Frid Lyngstad and Benny Andersson got together in a studio. After releasing their new album, "Voyage," the band is now slated to perform in London this May. Although the so-called "ABBAtar" holograms will replace the original singers, the band members could make an appearance in person.

ABBA's success story began with the song "Waterloo," which they performed at the Eurovision Song Contest in Brighton, England in 1974. From then on, band members Benny Andersson, Agnetha Faltskog, Bjorn Ulvaeus and Anni-Frid Lyngstad started an ABBA craze, which lasted the eight years of their band's existence. ABBA has sold more than 380 million records.

The year before their Eurovision win, ABBA didn't make it into the Swedish pre-selection of the contest. Perhaps this failure made their success the following year with "Waterloo" written by Benny Andersson (left) all the sweeter. Numerous hits followed; songs like "Dancing Queen," "Money, Money, Money," "Super Trouper," and "The Winner Takes it All" remain radio favorites to this day.

In 1977, ABBA went on their first world tour, performing in Europe and Australia, where they had many fans. In the same year "ABBA: The Movie" celebrated its world premiere in Australia. The group also performed for charity, including at the UN General Assembly in New York in 1979 (pictured). Even today, the proceeds from the hit song "Chiquitita," which was performed there, go to UNICEF.

What at first worked so harmoniously in the 1970s — pop music written and performed by two couples who were best pals — became strained by the 1980s. Both couples divorced, and in 1982 ABBA "took a break," as Lyngstad put it. But they haven't gotten back together since. Although two new songs were announced for 2019, they still haven't been released.

The official website of the Eurovision Song Contest announced in the summer of 2020 that five new ABBA songs could be released in 2021, according to the BBC. The band also wanted to go on tour as "ABBAtars" ― with holographic avatars playing on stage instead of the band members themselves.

While Agnetha and Frida have resumed their solo careers in recent years, Benny and Bjorn continued to work together, such as on the stage musical "Mamma Mia!" featuring ABBA songs. The production was turned into the 2008 movie of the same name, with a follow up in 2018 titled "Mamma Mia! Here We Go Again." Ulvaeus and Andersson are shown here at the latter's premiere.

Not many bands have a museum dedicated to them, but ABBA does. In 2013, ABBA The Museum opened in Stockholm and remains immensely popular. Among the interactive installations is a karaoke booth where visitors can record their voices singing along to the hits, and 3D holograms of the band members dancing, which will eventually tour in 2021.

ABBA have also been made into three-dimensional wax figures in the Stockholm Museum, where many of the band's eye-catching costumes can be found. In some parts of the interactive exhibition, visitors can learn the dance moves that go with the music. Once in a while, Frida, Bjorn, Benny or Agnetha even call the museum to talk to the lucky visitor who happen to be closest to the "Ring Ring" phone.