Then: Two of the most lucrative pop culture phenomena of 1999 were teen-pop and Mamma Mia!, the Abba musical that premiered in London that spring. Combining the two was a surefire win. The A-Teens - four photogenic teenagers from Sweden - did their best to step into the shoes of the original Abba, who split up years earlier. Their updated versions of hits including "Mamma Mia," "Super Trouper" and "Dancing Queen" scored big around the world.
Now: There are only so many Abba songs to cover, and soon the A-Teens ran out. They tried switching up the formula on later albums, covering Alice Cooper and Elvis Presley, but each disc sold worse than the last. The group split in 2004; all four A-Teens attempted solo careers, but none gained much traction outside of Sweden. While reunion rumors have circulated for years, the A-Teens remain defunct.