There has been lots of speculation about the origins of Baseball. Claims of invention in the USA, especially by Abner Doubleday in Cooperstown, seem fiction. Most likely baseball developed in the 17th/18th century in the USA based on European influences: mainly English 'stoolball' and 'cricket'. In the 2nd half of the 19th century baseball grew into a professional sport in the USA, which ultimately formed the American and National Leagues, who still form Major League Baseball today. Besides the USA (in which it's more than sport, it's called the 'national pastime'), the team sport is also very popular in the Americas and East Asia. The International Baseball Federation was founded in 1938. For more info see Wikipedia.

MLB (Major League Baseball)
Defunct Major Leagues:
AA (American Association)
AL (American League)
FL (Federal League)
NA (National Association)
NL (National League)
PL (Player's League)
UA (Union Association)

World Baseball Classic

Premier 12 Championship

European Championship

Pan American Games

Asian Games

Women: World Cup

Minor Leagues:
Triple-A National Championship
AAA:IL (International League)
AAA:PCL (Pacific Coast League)
AA:EL (Eastern League)
AA:SL (Southern League)
AA:TL (Texas League)
A:CalL (California League)
A:CarL (Carolina League)
A:FSL (Florida State League)
A:MWL (Midwest League)
A:NWL (Northwest League)
A:NYPL (NY-Penn League)
A:SAL (South Atlantic League)
Ind:AA (American Association)
Ind:AtlL (Atlantic League)
Ind:CAL (Can-Am League)
Ind:FroL (Frontier League)
Ind:NAL (North Amer. League)
Ind:PecL (Pecos League)
Defunct Minor Leagues:
AAA:AA (American Association)
AA:SA (Southern Association)
A:CenL (Central League)
A:GFL (Georgia-Florida League)
A:GFL (Lone Star League)
A:NL (Northern League)
A:WL (Western League)
Ind:CBL (Contin. Bas. League)
Ind:GBL (Golden Bas. League)
Ind:NL (Northern League)
Ind:SCL (South Coast League)
Ind:ULB (United League Bas.)

International Club Competitions:
Serie del Caribe Asia Series European Cup
Defunct Events:
European Cup Winners Cup CEB Cup European Super Cup

National Championships:
Mexico (Pacific)
South Korea

College Baseball:
NCAA Division I NCAA Division II NCAA Division III NAIA

World University Championships


Defunct Events:
Olympic Games
World Cup
Intercontinental Cup
World Games
W:World Series