(CNN) Finally, after 15 frustrating seasons, the Washington Nationals are going to the baseball mountaintop -- the World Series -- for the very first time.

The Nats beat the St. Louis Cardinals 7-4 on Tuesday night to wrap up a resounding four-game sweep and claim the title as National League champs.

Now the team will sit back and wait to see which American League team they'll face. The Astros beat the Yankees 4-1 in Game 3 at Yankee Stadium in New York Tuesday and lead the best-of-seven American League Championship Series two games to one. Game 4 is scheduled for Wednesday, weather permitting.

The Nationals started playing in the nation's capital in 2005 when the Montreal Expos moved there. The Nats enjoyed success -- and great disappointment.

Washington Nationals manager Dave Martinez celebrates after Game 4 of the baseball National League Championship Series.

The team won four NL East titles, only to lose every time in the first round of the playoffs. Sometimes the team was blown out.

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