To find more baseball history, you have to travel beyond the Big Leagues. Minor league ballparks date back even further than the oldest MLB stadiums. Centennial Field, in Burlington, Vt., saw its first game in 1906. The current grandstand was erected in 1922. Built on the University of Vermont's campus, the park is home to the Vermont Lake Monsters, an affiliate of the Oakland Athletics. Modest upgrades like permanent bathrooms and concession stands were added through the years, and the stadium now has a video scoreboard. Other than that, the 4,000-seat venue looks much as it did during its early days in the 1920s and '30s. Famous Revolutionary War hero Ethan Allen is buried in a cemetery that sits just beyond the outfield wall.