World History/Consequences of the Second World War
The Second World War saw the most far-reaching transformation of world politics to date. The destructive technologies introduced during the war – foremost, the atomic bomb – made it very unlikely that a land-based conflict of similar scale and duration among the major nations could ever happen again, because of the potential for total destruction of all combatants.
No advanced industrial nation has been invaded since 1945, and all wars since that time have either been guerrilla conflicts in less-developed countries, conflicts involving less-developed countries with more advanced ones, or some combination of these two scenarios.
From an economic standpoint, the war and its aftermath consumed much of the real and potential industrial production of the world over the period 1940-1960 (with the exception that the United States, its homeland untouched, was able to expand both its defense industries and its civilian economy very rapidly after 1945). Europe and Japan lay in ruins and would spend 15-20 years rebuilding the basis for economic life, with much assistance from the U.S. The Soviet Union and China, though victorious in the war, were also ravaged.
The splitting of the world 
Europe was split into two main camps by the "Iron Curtain", which divided Germany in half and separated Austria from Czechoslovakia and Hungary, and Italy from Yugoslvia. The Soviet Union absorbed eastern Poland, and "reassigned" large areas of German territory to Polish rule by way of compensation. Moscow intervened directly to install Communist parties in power in Poland, eastern Germany, Hungary and Czechoslovakia. Finland was able to keep its independence, but did not regain the lands it lost to the Soviets in the 1940 Winter War. Yugoslavia under Marshal Tito, already Communist, did not submit to direct influence from Moscow, choosing a more independent path and greatly angering Stalin. Elsewhere in the Balkans, Bulgaria, Romania and Albania also were brought into the Soviet bloc.
To the west were the democracies allied to the USA: the UK, France, Italy, the Netherlands, Belgium, Norway, and West Germany. Washington became quite concerned, however, that local Communist parties might gain power in France, Italy and Greece in the late 1940s, given the battered state of the postwar European economy and the proximity of the Soviet Union. French leader Charles DeGaulle received strong backing from the U.S., and anti-Communist parties in Italy were heavily financed. In the end neither nation left the Western sphere of influence.
In Asia China, Vietnam, Korea and Mongolia were communist countries, whereas Japan was occupied by USA and begun to build it's way from militarism to the democracy. Military alliances were form on both sides: NATO and Organization of Warsaw treaty.
Also, Organization of United Nations was established in 1945 in attempt to set up a body for possible dialog between Western, Eastern, and Developing countries.