The Boston Red Sox are an American professional baseball team based in Boston, Massachusetts, that competes in Major League Baseball (MLB). They are members of the East Division of the American League (AL). The Red Sox have won 8 World Series, having appeared in 12. Founded in 1901 as one of the American League's eight charter franchises, the Red Sox's home ballpark has been Fenway Park since 1912. The "Red Sox" name was chosen by the team owner, John I. Taylor, around 1908, following the lead of previous teams that had been known as the "Boston Red Stockings", including the forerunner of the Atlanta Braves. Boston was a dominant team in the new league, defeating the Pittsburgh Pirates in the first World Series in 1903 and winning four more championships by 1918. However, they then went into one of the longest championship droughts in baseball history, called by some the "Curse of the Bambino" after its alleged beginning with the Red Sox's sale of Babe Ruth to the rival New York Yankees two years after their world championship in 1918, an 86-year wait before the team's sixth World Championship in 2004. The team's history during that period was punctuated with some of the most memorable moments in World Series history, including Enos Slaughter's "mad dash" in 1946, the "Impossible Dream" of 1967, Carlton Fisk's home run in 1975, and Bill Buckner's error in 1986. Following their victory in the 2013 World Series, they became the first team to win three World Series trophies in the 21st century, including championships in 2004 and 2007. Red Sox history has also been marked by the team's intense rivalry with the Yankees, arguably the fiercest and most historic in North American professional sports. The Boston Red Sox are owned by Fenway Sports Group, which also own Liverpool F.C. of the Premier League in England. The Red Sox are consistently one of the top MLB teams in average road attendance, while the small capacity of Fenway Park prevents them from leading in overall attendance. From May 15, 2003 to April 10, 2013, the Red Sox sold out every home game—a total of 820 games (794 regular season) for a major professional sports record.

Fenway Park

The Seattle Mariners are an American professional baseball team based in Seattle. The Mariners compete in Major League Baseball (MLB) as a member club of the American League (AL) West Division. The team joined the American League as an expansion team in 1977, playing their home games in the Kingdome. Since July 1999, the Mariners' home ballpark has been T-Mobile Park, located in the SoDo neighborhood of Seattle. The "Mariners" name originates from the prominence of marine culture in the city of Seattle. They are nicknamed the M's, a title featured in their primary logo from 1987 to 1992. They adopted their current team colors – navy blue, northwest green (teal), and silver – prior to the 1993 season, after having been royal blue and gold since the team's inception; the original colors continue to be used in alternate uniforms. Their mascot is the Mariner Moose. The Mariners did not field a winning team until 1991, and further success eluded them until the late 90s, the most successful period in franchise history. Led by Hall of Fame players Edgar Martínez, Ken Griffey Jr., and Randy Johnson, the Mariners clinched their first playoff berth in 1995 when they won their first division championship and defeated the New York Yankees in the ALDS. Martínez's walk-off double in Game 5 drove Griffey in from first base to win the game in the 11th inning, clinched a series win for the Mariners, served as a powerful impetus to preserve baseball in Seattle, and has since become an iconic moment in team history. They would later win their second division title in 1997. After Griffey, Johnson, and Alex Rodriguez all left the team, the Mariners, bolstered by the signing of Ichiro Suzuki, won 116 games in 2001, which set the American League record for most wins in a single season and tied the 1906 Chicago Cubs for the Major League record for most wins in a single season. The team would not make the postseason again until 2022, which was the longest active drought in the four major North American sports. As of 2024, the franchise has finished with a losing record in 30 of 48 seasons. The Mariners are the only active MLB franchise never to have appeared in the World Series, currently holding the longest active World Series appearance drought in MLB.