The cold war is a long trial of strength that began in the aftermath of the capitulation of Hitler Germany between the United States and the Soviet Union. In the middle of the war, in 1941 the break of the non-aggression pact instantaneously made the soviet regime a ally of the occidental democracies. But, at the end of the second world war, their divergent point of views regarding the path to follow in the post-war era have opposed yesterday allies.Step by step, both super powers built their own zones of influence and divided the world into two camps poles apart from each other. In fact the “cold war” was not exclusively a Soviet-American conflict yet a global conflict that will impact in a way or another many countries in the world, including the European continent. This one, divided into two blocks, became indeed one of the major theaters of the confrontation. In western Europe, the European integration process is heavily supported by the United States, while the eastern European countries became what we call “soviet satellites”.From 1947, the two opponents, using all their intimidation resources will oppose in a long strategic and ideological conflict marked with more and more violent crisis. Even if both of them never opposed them self in a direct way, they, in different occasions, brought the world to the brink of an atomic war that no one desired. Only nuclear dissuasion prevented them to enter in a direct military confrontation. Paradoxically, this “balance of terror” stimulated both camp to win the so called “arm race”. The phases of tension alternate with periods of relaxation or warming of relations between the two camps. The cold war will finally end in the symbolic date of 1989 which coincides with the fall of the berlin wall and the following crash of all communist regimes in the eastern European counties. Toward a bipolar world (1945-1953) The end of the second world war doesn’t bring the world toward normality and peace yet, in the contrary announces the emerging of a new conflict. Whilst the European powers that were master of the international scene in the 30s are tired and exhausted by the effort and destruction that war brought, two new superpowers rule the international arena. Two blocks strated forming around, in one hand, the soviet union, and in the other hand, the United States of America. The rest of the world must align within one camp or the other.Territorially expanded, the USSR came out from the war with the image of a freedom fighter against the barbary of Hitler’s Germany. They are galvanized by their heroic resistance against the enemy as the Stalingrad victory testifies. The USSR also offers an ideological, economic and social model that shine as never in Europe. Furthermore, in opposition to the American army, the red army didn’t demobilize at the end of the war which gave them a real competitive advantage in terms of men’s and heavy artillery.The USA are the real winners of the second world war. Their human and non-human losses are relatively low compared to the other war participant and even if the American troops are almost totally demobilized few months after the war they still are the first military power in the world. Their navy and their air force have no equal, moreover they had the atomic monopoly until 1949. Furthermore they can also claim to be the world’s number one economic power, both in terms of trade volume and industrial and agricultural production. Americans now own two-thirds of the world’s monetary gold and the dollar is the international currency of reference.Step by step, conflicts of interest between the new global superpowers follows one other in a atmosphere of distrust and fear. Each of them fears the new power of each other. The soviets feel surrounded and threatened by the occidentals and accuse the united states to drive an imperialist expansion. In the other hand, the Americans are worried about the communist expansion and blame Mr. Stalin for not respecting the Yalta agreement on the right of the liberated peoples to self-determination. The resul of this situation is a long period of international tension summoned by big crises that led sometimes on local military conflicts yet without triggering an open war between the United States and the USSR. The Cold War reaches its first strong moment during the Berlin blockade. The explosion of the first Soviet atomic bomb in the summer of 1949 strengthened the USSR’s position as a world power. This situation confirms the predictions of Winston Churchill who, in March 1946, is the first Western statesman to speak publicly about an “iron curtain” which now cuts Europe in two.Missed peace The second world war has shaken the world map. The human and material balance sheet is the heaviest that humanity has ever known. A tired and breathless Europe is ruined and on the merge of total chaos: factories and communication routes almost totally destroyed, commercial trade not existing anymore, shortages of raw materials and consumer goods.Even before the effective capitulation of the Axis countries, the Big Three, Americans, English and Russians, are trying to settle the fate of the post-war world. From November 28 to December 2, 1943, the Tehran Conference is the first summit meeting between Winston Churchill, Joseph Stalin and Franklin D. Roosevelt. It outlines the main lines of post-war international politics. The leaders speak in particular about the landing in Normandy, then fixed on May 1, 1944, of the fate of Germany and its eventual dismemberment as well as the organization of the world in the aftermath of the conflict. They decide to entrust the study of the German question to a European advisory commission. Two other allied conferences will follow, one in Yalta (from 4 to 11 February 1945), the other in Potsdam (from 17 July to 2 August 1945).But very soon, the close alliance of war gets replaced by mistrust. At peace conferences, the Big Three quickly realized that increasingly divergent points of view were opposing Westerners and Soviets. The old antagonisms that war has silenced were resurging and the Allied Powers are failing to agree on a peace treaty.