Former U. S. President Bill Clinton (C), Swiss actor and Academy award winner Maximilian Schell (L) and German actress Sunny Melles perform on stage during the Red Ribbon Celebration Concert ahead of the 20th Life Ball at Vienna's international airport May 18, 2012. The Life Ball is Europe's largest annual AIDS charity event and takes place in Vienna's city hall May 19, 2012. REUTERS/Leonhard Foeger (AUSTRIA - Tags: ENTERTAINMENT POLITICS)