The World Series has been the annual championship series of the highest level of professional baseball in the United States and Canada since 1903, concluding the postseason of Major League Baseball. Since the Series takes place in October, sportswriters many years ago dubbed the event the Fall Classic; it is also sometimes known as the October Classic or simply The Series. It is played between the League Championship Series winning clubs from MLB's two circuits, the American and National Leagues. The World Series has been played every year since 1903 with the exception of 1904 (boycott) and 1994 (player strike). Though professional baseball has employed various championship formulas since the 1860s, the term "World Series" is usually understood to refer exclusively to the modern World Series.