In this June 14, 1974, file photo, members of the Swedish pop group ABBA, Benny Andersson, back left, Bjorn Ulvaeus, back right, Anni-Frid Lyngstad, front left, and Agnetha Faltskog, are shown.
Millions have seen 70s Abba brought back to life in their hologram show. Now Queen could go one further with similar concerts that bring frontman Freddie Mercury back from the dead. Queen guitarist ...