Major League Baseball (MLB) is the premier professional baseball league in the United States and Canada, consisting of 30 member clubs. Established in 1903 through the merger of the National League and the American League, MLB has a rich history that dates back to the formation of the Cincinnati Red Stockings, the first all-professional team, in 1869. The league is currently led by Commissioner Robert D. Manfred, Jr. MLB organizes and operates professional baseball competitions, with the World Series being its flagship event. This annual championship, which began in 1903, determines the national champion by matching the winners of each league. MLB also oversees 31 stadiums that serve as home fields for its teams. The league is dedicated to making a positive impact in communities across the U.S., Canada, and globally through various business and social responsibility initiatives.