Ten years ago Wednesday, Jon Favreau’s Iron Man soared into theaters, marking the first shot fired in the Marvel Cinematic Universe. The film, released May 2, 2008, changed the game forever, though it wasn’t instantaneous. Nothing as massively successful as this possibly could be. But it was the introductory step in what would ultimately yield a 19-film (and climbing) on-screen tapestry that this past weekend culminated in the biggest opening weekend in movie box office history.