Security Forces have transformed dramatically in the last twenty years. This transformation has been a continuous process, but may be broken into three distinct periods separated by key events: the 1996 attack on Khobar Towers, Saudi Arabia and the September 11, 2001 attack on the World Trade Centers and the Pentagon. Each distinct phase of Security Forces transformation differed with respect to mission, organization, deployments, and training, requiring Security Forces to change mission focus to meet the emerging challenges.