Festival-goers cheer in front of a stage at the Donauinselfest (or Danube Island Festival) in Vienna June 24, 2011. The three-day Donauinselfest consists of a 4.5 km (2.8 miles) festival area, involves 2,000 performing artists and is expected to draw around 3 million visitors in the largest open air festival in Europe, according to organizers.REUTERS/Lisi Niesner (AUSTRIA - Tags: ENTERTAINMENT SOCIETY)