ABBA

Enormously popular if slightly unhip during their nine-year tenure, ABBA remained a major presence in pop culture decades after their breakup. Björn Ulvaeus and Benny Andersson initially teamed as a songwriting duo in 1966, one of their early songs "Speleman" ("Fiddler") being a Swedish hit for Andersson's group the Hep Stars. Their first duo album, the 1970 Swedish release Lycka, included vocals by Ulvaeus' wife Agnetha Fältskog and Andersson's fiancée Anni-Frid (Frida) Lyngstad.

The two couples sang and socialized together over the next two years, and released a few singles under their individual names. ABBA was officially christened with the February 1973 release of "Ring Ring," which failed as a Eurovision Song Contest entry but clicked (with English lyrics added by Neil Sedaka) as a Swedish chart single. They re-entered the Eurovision contest with the following year's "Waterloo," which not only won the contest but was an international hit, going Top 10 in the US and topping charts in the UK.

During a decade that saw the rise of glam, punk, arena-rock and disco, ABBA remained unstoppable, their sweet romantic image and effervescent pop sound standing apart from the trends of the day (though they did embrace disco on 1976's "Dancing Queen," a song that would soon be embraced by gay culture). While early hits "I Do, I Do, I Do, I Do" and "Mamma Mia" were cheerful pastiches of Connie Francis and Phil Spector, the later hits got more daring, with "Money, Money, Money" referencing German cabaret and "The Winner Takes It All" being a full-fledged torch ballad.

Their most danceable album, 1979's Voulez-Vous spawned a world tour that proved to be their longest and last. By now there was tension behind the scenes-- Ulvaeus and Fältskog were divorced in 1980, Andersson and Lyngstad in 1981-and their music took a darker turn to match: A line like "These walls have witnessed all the anguish of humiliation" would have been unthinkable in an ABBA single before 1981's "The Visitors." Though they never formally disbanded, ABBA effectively ended with the collapse of their next album in 1982.

There were two more ABBA-related hits in the US, with Frida's "I Know There's Something Going On" (recognizably produced by Phil Collins) and Murray Head's "One Night in Bangkok," the single from Ulvaeus and Andersson's musical Chess. However, ABBA's afterlife was just beginning. Two 1994 films, "The Adventures of Priscilla, Queen of the Desert" and "Muriel's Wedding," both made campy, affectionate use of ABBA's music, and numerous touring tribute bands sprang up, including GABBA who made two albums of ABBA songs in Ramones style (and vice versa).

The musical Mamma Mia! opened in the West End in 1999 and spawned a 2008 film starring Meryl Streep and many international productions, forever linking ABBA with the spirit of the '70s. The group members continued to make occasional recordings and promo appearances, and in 2005 all four appeared at the musical's opening in Stockholm. They appeared onstage once again in June 2016, at a private party in Stockholm-and this time there was a song performed, as the two women sang the ABBA song "The Way Old Friends Do."

Despite numerous rumors and pleas from fans, this is as close as ABBA has ever gotten to a reunion.