The Cardinals–Royals rivalry (also known as the Show-Me Series or I-70 Series) is a Major League Baseball (MLB) interleague rivalry between the St. Louis Cardinals of the National League (NL) Central division and the Kansas City Royals of the American League (AL) Central division. Both teams played against each other for the first time in the 1985 World Series, which the Royals won 4-3. Owing to their geographical proximity, these two teams face each other every regular season in interleague play (a setup known as a "natural rivalry").