This Swedish quartet (well, Swedish trio and one Norwegian) were once know as Festfolk meaning either "engaged couples" or "party people". 1976 was a good year for Abba: three UK number one hits - "Mamma Mia", "Fernando", and "Dancing Queen". "Dancing Queen" was their only number one hit in the US.
Their music was irresistibly popular thanks to ultra-catchy tunes, disco beats and the unique mix of the four voices.
Abba
