The 2012 Summer Paralympic Games begin tonight in London with Queen Elizabeth II officially opening the Games at the Opening Ceremony in London. An estimated 4,200 athletes representing 167 countries are expected to compete in the Games, designed for athletes with physical disabilities. They will compete in 20 sports, ranging from cycling, powerlifting, and judo, to wheelchair rugby and goalball. In the UK, Channel 4 is inviting viewers to "Meet the Superhumans," and it plans to broadcast 150 hours of Paralympic programming between now and the Closing Ceremony on September 9. Viewers online can also watch hundreds of hours of live video from the International Paralympic Committee at paralympic.org. Gathered here are images of the athletes and organizers as they ready themselves for the 2012 Summer Paralympics -- more coverage to come as the Games progress.