Complex sentence: The Subway Series is a series of Major League Baseball (MLB) rivalry games played between teams based in New York City; every historic and current venue for such games has been accessible via the New York City Subway, hence the name of the series.
Split into simpler sentences: The Subway Series is a series of Major League Baseball (MLB) rivalry games played between teams based in New York City. Every historic and current venue for such games has been accessible via the New York City Subway, hence the name of the series.