Hailing from Stockholm, Sweden, they remain the most commercially successful pop group of the 1970s. Their name, ABBA, was taken from the acronym formed by the first letters of each of the group members' given names (Agnetha, Björn, Benny, Anni-Frid). They gained immense international popularity employing catchy song hooks, simple lyrics, and a Wall of Sound achieved by overdubbing the female singers' voices in multiple harmonies. As their popularity grew, they were sought after to tour Europe, Australia, and North America, drawing crowds of near-hysterical fans, especially in Australia. To this day they remain a fixture of radio playlists everywhere and are one of the world's best selling bands, having sold over 370 million records worldwide. They still sell two to four million records a year.