8. The Spanish Civil War (1936-1939)
The Spanish Civil War began in July 1936 as an internal conflict between the Republican government and Nationalist forces led by Francisco Franco. Despite the Non-Intervention Agreement signed by 27 nations, including Germany, Italy, and the Soviet Union, these countries provided substantial support to their respective factions without formal declarations of war (encyclopedia.ushmm.org). This involvement transformed Spain into a battleground for competing ideologies, serving as a precursor to World War II.
