"Happy 94th birthday to Nelson Mandela. You're my hero, and your selflessness, your vision, and your courage are an inspiration to everyone. Your greatest service was to teach the world that 'impossible' is just a myth. Today all of us should take some time to reflect on Mandela's great wisdom: 'It always seems impossible until it's done.' After you reflect, go out and do the impossible. It's the best way to celebrate this great man." Action man Arnold Schwarzenegger salutes the former South African president and civil rights icon on his special day.