Guerrilla war is a form of irregular warfare where small groups use tactics like ambushes, sabotage, and hit-and-run attacks against larger traditional military forces. This strategy relies on mobility, surprise, and the support of the local population to disrupt and weaken the enemy. Typically, guerrilla fighters operate in familiar terrain, such as forests or mountains, making it difficult for conventional armies to engage them effectively. Historical examples include the Vietnam War, where the Viet Cong used guerrilla tactics against U.S. forces, and the Spanish Civil War, where guerrilla fighters resisted Franco's regime.