The 1969 Major League Baseball season was celebrated as the 100th anniversary of professional baseball, honoring the first professional touring baseball team, the Cincinnati Red Stockings.

It was the first season of what is now called the "Divisional Era," where each league of 12 teams was divided into two divisions of six teams each. The winners of each division would compete against each other in a League Championship Series, then best-of-five, to determine the pennant winners that would face each other in the World Series.

In a year marked by the second expansion of the decade, the New York Mets and the Baltimore Orioles faced each other in the 1969 World Series. Having won the N.L. East Division with a league-best 100–62 record, and sweeping the N.L. West Division Champion Atlanta Braves in three games in the first National League Championship Series, the "Miracle Mets" became the first expansion team to win a pennant. They faced the A.L. East Division Champion Orioles, holders of the best record in baseball (109–53), who swept the A.L. West Division Champion Minnesota Twins in three games in the first American League Championship Series. The upstart Mets would upset the heavily favored Orioles and win the World Series title in five games. Taken from http://en.wikipedia.org/wiki/1969_Major_League_Baseball_season.