Few songs from the 1970s still get people talking quite like this ABBA hit. "Waterloo" started as an upbeat fan favorite, went on to become one of the group's most recognizable early successes.

One of ABBA'smost popular songs, selling more than six million copies after its release in 1976, was originally called "Tango." The best-seller was first released as a solo single for Anni-Frid "Frida ...