Agnetha, Bjorn, Benny and Anni-Frid were the biggest global pop phenomenon of the 1970s. Their 1974 Eurovision win led to an unbroken string of hits around the world and in recent years their music has enjoyed an unparalleled revival. From ABBA to Mamma Mia features more than 500 photographs by Anders Hanser, a close friend of the band who has had unprecedented access over more than 20 years. The result is a snapshot of life with ABBA behind closed doors: relaxing in a private jet in the US, departing from Wembley arena by limo and backstage at numerous concerts.