More than 18 million people have already seen international and national music highlights such as U2, Robbie Williams, Bon Jovi, AC/DC, Bruce Springsteen, Metallica, Herbert Grönemeyer or PUR, listened to opera productions such as Carmen and Aida or cheered on sporting events such as the biathlon at Schalke, the world record attendance at the 2010 Ice Hockey World Championships, the Klitschko boxing events and the 2004 Champions League final.