The Swedish band ABBA succeeded in stringing together superlatives during their career: they have sold 400 million records to date, their singles have been at number one in 23 countries a total of 124 times, and in the album charts ABBA reached number one 78 times in 21 countries. Finally, in 2010, they were inducted into the "Rock And Roll Hall Of Fame". ABBA became the most successful pop band of the 1970s with their catchy melodies, their easy-to-understand lyrics and their "wall of sound" productions, in which they recorded the vocals several times over.