 This resulted in crucial limitations in Germany's Kriegsmarine against the Royal Navy.The interwar years in Europe were brought to a close by the Spanish Civil War of 1936 to 1939.This conflict was a prelude to the World War II, both in new technologies used (strategic and tactical aerial bombing, mechanized warfare, direct attacks on civilian populations, guerilla operations) and belligerents (Fascist Italy and Nazi Germany supporting the Nationalist side, Communist Russia and various European leftist groups supporting the Loyalist side).