Interleague play

The interleague play happens when the American League and National League face off in one weekend in May and starting again from one weekend in early June ending on one weekend in late June. It happens in the World Series and All-Star Game too.

First times
The first interleague game took place on June 12, 1997 which ended up being the San Francisco Giants against the Texas Rangers in the Rangers Ballpark at Arlington during the day. Darren Oliver throught the first interleague pitch. The first designated hitter during the regular season to a National League player was Glennallen Hill that game. Stan Javier of the Giants hit the first interleague homerun which they eventually won by in a score of 4-3.

From 1998 onto 2001, both west divisions faced eachother. In 2002, the American League East was against the National League West, the American League Central faced off against the National League East, as the American League West battled the National League Central. Ever since 2005, there has been May interleague games on one weekend.

Rivalries
Chicago Cubs against the Chicago White Sox in the Windy City Rivalry

Cincinatti Reds against the Cleveland Indians in the Ohio Cup

Los Angeles Dodgers against the Los Angeles Angels in the Freeway Series

New York Yankees against the New York Mets in the Subway Series and Yankees-Mets Rivalry

San Francisco Giants against the Oakland Athletics in the Bay Bridge Series

St. Louis Cardinals against the Kansas City Royals in the Royals-Cardinals Rivary

Minnesota Twins against the Milwaukee Brewers in the Brewers-Twins Rivalry