When X-Men: First Class debuts in theaters today, we'll meet the mutants as their younger selves in the 1960s. However, the onscreen mutants we know best are the ones that have appeared in the four previous movies, like Hugh Jackman and Patrick Stewart. So before you hit the theater and meet the mutants decades ago, first go back to 2000 and meet them in the first X-Men movie. In the trailer below, you'll see Stewart as Professor X in all his bald glory, as well as Rebecca Romijn stealing the show as Mystique. Can't get enough? Check out my slideshow of the older and younger X-Men characters!