Major League Baseball

Major League Baseball (MLB) is a professional baseball league in North America. It is often considered to be the highest level of professional baseball in the world. There are two leagues that make up the MLB: the American League, also called AL, and National League, also called NL. There are currently 30 teams in the MLB, 29 from the United States and one from Canada, the Toronto Blue Jays.
The official website of MLB is known as "MLB.com" (www.mlb.com).
Major League Format
The 30 teams in MLB are divided into two leagues: American and National. Each league is divided into three divisions: East, Central, West. Since the 2013 season, each division has had five teams. The most recent change took place after the 2012 season, when the Houston Astros moved from the NL Central to the AL West.
Each team in Major League Baseball is scheduled to play a 162-game season. The season begins in April (or sometimes the end of March) and ends in October. The teams play other teams in their own division the most, and play very few (no more than six) games against teams in the other league. Teams usually play each other in series of three or four games at a time. If a game is canceled because of bad weather, it may be held later, sometimes as part of a doubleheader (two games in one day). Sometimes these games are not held again if it would not affect either team's place in the standings (the list of teams ordered by their number of wins and losses).
Highest ranking teams after this regular season enter a post-season of "playoff" games. Teams that are tied at the end of a season may play another game to decide which team(s) will enter the playoffs. The playoff games determine the champion for each of the two leagues.
In July, there are three days where teams do not play normal games, and a group of the best players play in the "Major League Baseball All-Star Game". This period is called the "All-Star Break", and it is thought of as the point where half of the season is over. Some games at the beginning of the regular season have been played in other countries, such as Japan.
Playoffs
At the end of every season, ten teams play in the playoffs. Five teams from the AL, and five teams from the NL are in the playoffs. The team from the West, Central, or East division from each league with the most wins makes the playoffs (a team with the best record in its division is said to have "won its division"). The next two best teams in the AL and the next two best teams in the NL also get to play in the playoffs. They are called "wild card" teams. The first playoff round is called the Wild Card game. The two wild card teams from each league play each other in a one-game playoff. The winner of each game moves on to the Division Series. The team with the best record in each league plays the winner of its league's Wild Card game. The division winner with the second best record plays against the division winner with the third best record.
In the Division Series, teams play "best out of 5". Once one team beats the other three times, the winning team moves onto the next round of the playoffs, the Championship Series. The teams that lose are out of the playoffs. The AL teams that win play in the AL Championship Series. The NL teams that win play in the NL Championship Series. The Championship series is "best out of 7 games". Once one team beats the other four times, the winning team moves onto the next round of the playoffs. After the Championship Series, there are only two teams left.
World Series
These two teams play each other in the World Series, which is also a "best out of 7 games" series. The winner of the World Series is the champion of the league. They receive a trophy, depicting flags at different heights.
History
The first league of professional baseball teams began in 1871 and was called the National Association. This league did not play baseball the same way MLB does. For example, batters would walk after nine pitches instead of four. Many of the teams had problems with money and split up after only one or two seasons. However two teams are still playing today. Those teams were the Boston Red Stockings, which today are the Atlanta Braves, and the Chicago White Stockings, which today are the Chicago Cubs.
In 1876, the National League began, and included the Red and White Stockings as well as six other teams. This league was run better, but many teams still would split up after only a few seasons. Some, like the teams that are now called the Philadelphia Phillies and San Francisco Giants, are also still playing today. There were other leagues also. The American Association started in 1882 and was almost as good as the National League. However many of its teams would go to the National League, and the American Association disappeared in 1891. The National League had problems, though. Players and fans did not behave well, and in 1894 a fire started during a game and destroyed the stadium and part of Roxbury, Boston.
Teams
A star (*) means a relocation of a franchise. See team articles for more information.