Reconnaissance, which in military terms means exploration and collecting information, has always been crucial to warfare. Such units operate ahead of the main forces, gathering data on the enemy, the terrain, and other factors of interest. Virtually all land-based countries employed Scouts of some kind, both for their stealth capabilities and mobility. A later example of traditional Scouts were the US Army Indian Scouts employed by the government between 1866 and 1947, taking part in numerous military actions like the American Civil War or the campaign against Pancho Villa.