As the weather cools and the leaves begin to turn, it’s one of America’s greatest traditions—the start of football season. Lights come up on Friday night high school games across the country. On Saturdays, college campuses, from South Bend to Tuscaloosa, flood with faithful fans, coming together to tailgate and celebrate time-honored game-day traditions. But the biggest games are on Sundays, when the stadiums of the National Football League put on a show. And while most will simply turn on their televisions and enjoy the spectacle of the big passes, the turnovers, the views from the Goodyear blimp—you can build a whole vacation around a trip to an NFL matchup. In many cases, the stadiums themselves are worth the journey, from historic and hallowed places like Lambeau Field in Green Bay, to gleaming new mega-complexes like the $5.5-billion SoFi Stadium in Los Angeles. And it’s about more than the game—these …