The Super Bowl is an enormous night for international television. Last year, an estimated 111 million people watched the game, its advertisements and its halftime show. It all begins with the performance of the National Anthem, a tradition that has been carried out by some of the greatest voices in pop music history. The song isn't easy to deliver – as Christina Aguilera discovered last year – but there have been some exceptional performances. Click through to see the best star-spangled renditions.