No matter how old an NFL rivalry is, one thing always remains the same—these teams and fans really hate each other.

Whether a matchup dates back to leather helmets or was formed after the AFL-NFL merger, these teams always circle their battles on the calendar and hold nothing back once the whistle blows. Fans fighting in the stands, players fighting on the field, and injuries on the gridiron are commonplace in these matchups—and teams are never happier than when they can claim victory over a rival.

Here are the top 10 most intense team rivalries in NFL history: