In the United States and United Kingdom, a black project is in the vernacular a highly classified military/defense project, unacknowledged publicly by the government, military personnel, and defense contractors. Examples of U.S. military aircraft developed as black projects include the F-117 Nighthawk stealth attack aircraft and the B-2 Spirit stealth bomber, both of which were highly classified and denied to exist until ready to be announced to the public. In the United States the formal term is Special Access Program (SAP). A black site is a location where a black project takes place.