The 20th century was, from my viewpoint, a century of major changes. At the outset of the 1900s, in 1914, WWI broke out demonstrating a totally new face of combat. Machine guns, heavy artillery, and war planes were tried for the first time after the sword and shield had been the basic fighting tools for the previous thousands of years. Almost 20 years later, WWII took place causing even more destruction than the preceding war. People thought that another change in the style of warfare was hundreds of years away. This projection was, obviously, incorrect. Another type of war, The Cold War (CW), grew out of WWII.I would define the CW as a war with no physical fighting, and a period of threat, intimidation, and conflicting ideologies. These three keywords are important because they brought many results. Threat and intimidation led to a build-up of arms, the formation of political organizations that work together against the enemy, and the use of other countries to work against the enemy. On the other hand, conflicting ideologies led to arguments between the leaders and to the exploitation of propaganda and media. However, it is difficult to identify a starting point for the CW. The main reasons are that there was no significant gap between WWII and the CW, there was no physical battle to mark the beginning of the war, and most of the events following WWII didn’t fulfill all of the characteristics of the CW.The Yalta and Potsdam conferences partly fit my definition of the CW. Most of the sources linked to the Yalta conference support the ‘threat and intimidation’ factor by highlighting the uneasiness and suspicion between the leaders. A couple of sources even stated that Churchill was preparing his army for an attack on Russia- ‘build-up of arms’. Additionally, the Potsdam conference clearly portrays a build-up of arms on the American part and conflicting ideologies between Truman and Stalin. I think that the main surprise at this conference was the declaration of the Americans’ Atomic Bomb, even though it is said that Stalin knew about the project through espionage way before Truman. Also, Truman and Stalin argued over Stalin’s control over eastern Europe and his colonial intentions in it, whether to rebuild Germany, and whether to demand reparations from Germany. Although these two conferences represented many CW characteristics, they lacked a few others. Because these two conferences were supposed to be peaceful and constructive meetings between the Allies, no propaganda was employed, and no opposing organizations were created.Other events also fit my definition to some extent. To begin, the Communist takeover in eastern Europe introduced propaganda for the first time since WWII, showed the global misinterpretation of the takeover, increased the western apprehension, and illustrated the struggle over leadership between the local leaders and the USSR. However, this incident lacked an arm’s race and the use of other countries against the enemy. Furthermore, Greece became the highest point of tension since the end of WWII. With the communists sparking a civil war against the royalists, the USSR backing up the Greek communists, and Britain and America supporting the royalists, the CW was close to changing into a physical war.In Greece, there was certainly a great deal of arguments between leaders, as well as the use of Greece by the powers to attack each other. On the contrary, there was no build-up in arms and only some weak propaganda. The Truman Doctrine is another example of conflicting ideologies and mutual fear because the US launched it for the west’s protection whereas the USSR saw the doctrine as a military alliance against it. The doctrine also promoted some propaganda and a major exploitation of the western countries against the USSR. In this case, though, there is no argument between leaders and no build-up of arms.At this point on the timeline, “Marshall Aid” was in the making. The Americans wanted to use it to work through the other countries against communism because they thought a prosperous Europe would expel communism. As a result a lot of propaganda spread and the USSR banned all communist states from accepting Marshall Aid because Stalin thought it was a danger. Like the doctrine, there was, still, no increase in weapons or arguments between the leaders. The American Congress disapproved of Martial Aid until the communists overthrew the coalition government in Czechoslovakia and killed a pro-American leader. This event embodies a disagreement between the USA and the USSR, which provokes a dispute between the two nations, major use of propaganda on how the pro-American Czech leader died. These were the major characteristics of the Czech incident; the list was not completed until the Berlin Blockade.Finally, all these elements seem to be in place together by the time of the Berlin Blockade. To begin, the blockade caused another flow of conflicting ideologies and arguments. The Americans considered the blockade to be a test they were put into by Stalin and a new Russian attempt to expand in Europe. The USSR considered it as a form of protecting their economy from the currency newly introduced in West Germany and shielding itself from a recovered Germany. Moreover, as shown in the sources, negating facts and statistics about the blockade and the airlift boosted the amount of propaganda to the peak. At the highest point of the struggle, the NATO was formed, a military organization comprising several countries against the USSR. The NATO frightened Stalin and encouraged and arms race on both sides.Therefore, I conclude that the Cold War was definitely underway by the Berlin Blockade. The Berlin Blockade was a climax of many actions that led up to it. Because it was the climax, the other events were lacking some extra characteristics to make them significant enough to start a war. Of course this is only my opinion if I had to choose only one event. Otherwise I would say that it is almost impossible to choose one definite event. One reason is that the list of criteria that I depended on to reach my conclusion is not perfect and maybe incomplete. Therefore, using another list could bring me to another conclusion. Historians until today debate their different viewpoints on the CW.