The Revolutionary Insurgent Army of Ukraine (UPA) was a Ukrainian nationalist military formation that operated during and after World War II. Established in 1942, it aimed to fight for Ukrainian independence from both Nazi Germany and the Soviet Union. The UPA was associated with the Organization of Ukrainian Nationalists (OUN) and engaged in guerrilla warfare, targeting both occupying forces and local collaborators. The UPA's activities were marked by significant conflict and controversy, including accusations of ethnic cleansing against Polish populations in western Ukraine. The army's legacy remains complex, as it is viewed by some as a symbol of resistance and by others as a perpetrator of violence. Its role in Ukrainian history continues to be a topic of debate.