THE CHACO WAR, 1932-1935: Bolivia started the Chaco War to gain access via the Rio Paraguay to the Atlantic Ocean. To do that it’s army had to wrest the sparsely populated 100,000-square-mile Gran Chaco from Paraguay. (Map By Baker Vail, www.bakervail.com) This map appeared in “Battle in the Barrens” from the Summer 2009 issue of Military History Quarterly.