One of the Rainbow Plans, War Plan Black was the name of an American military plan to fight Germany in the early 20th century. The best-known version was conceived as a contingency plan during World War I in case France fell and the Germans attempted to seize French possessions in the Caribbean or to launch an attack on the eastern seaboard. The United States was to plant mines and have submarines on patrol at sites Germany might seize for a foothold in the Caribbean. The plan was revised in 1916 to concentrate the main US naval fleet in New England, and from there defend the US from the German navy. Following Germany's defeat, the plan lost importance.