Some conflicts between the West and the USSR appeared earlier. In 1945–46 the US and UK strongly protested Soviet political takeover efforts in Eastern Europe and Iran, while the hunt for Soviet spies made the tensions more visible. However historians emphasize the decisive break between the US–UK and the USSR came in 1947–48 over such issues as the Truman Doctrine, the Marshall Plan and the Berlin Blockade, followed by the formation of NATO in 1949.The Cold War took place worldwide, but it had a partially different timing outside Europe.