which is nicknamed the Beltway Series. The teams have played two series a season – one in Baltimore and one in Washington – since 2006. The Nationals and Orioles rivalry is one of the few that can be played in a World Series. Notes References External links FOX Sports – Washington Nationals team front Sandalow, Marc. "A Brand-New Ballgame: The New Stadium of the Nationals", Washingtonian, March 1, 2008. 2005 establishments in Washington, D.C. Grapefruit League Major League Baseball teams Privately held companies based in Washington, D.C. Baseball teams established in 2005