The Boston Red Sox are a Major League Baseball team based in Boston, Massachusetts. The team is a charter member of the American League East Division. They play home games at Fenway Park, which opened on April 20, 1912, making it the oldest major league ballpark still in operation. The Red Sox won the first World Series as the Boston Americans in 1903 against the Pittsburgh Pirates. They won their most recent World Series championship in 2004, after an 86-year interval. The Yankees-Red Sox Rivalry is one of the longest standing and most storied rivalries in North American sports.