A pivotal event in the past is one, that has caused a significant change in the course of history. Significant events have and will always have an influence on the continuation of time and this in a way makes every event pivotal. What sets apart the critical turning points of history from day to day occurrences is the long term effects of these events. The most pivotal events in history are ones, that have the most drastic long-term effects. World War II was a pivotal event in US history but every large event can be broken down into smaller key events. The single key event that brought the end to this awful war and can be argued as the most glorifying or the most evil event in US history, was the detonation of the atomic bombs on Hiroshima and Nagasaki. The act alone of detonating these weapons of unfathomable destruction can be considered a pivotal event in itself. However these weapons did not just come from out of the blue. The technology for this new and exponentially more powerful weaponry than had ever existed emerged from an even more influential event, the Manhattan Project. The Manhattan Project is truly one of the most pivotal events in US history because its discoveries had extreme long-term effects that drastically changed the history of the US as well as shaped the world today. On, October 11, 1939, a letter from Albert Einstein was delivered to President Roosevelt that provided the context for the development of the Manhattan Project. The letter warned Roosevelt about the existence of the German nuclear energy project. At this point the United States was neutral in the war, however Einstein made clear the dangers of the possibility of an atomic bomb in the hands of the Germans and advised Roosevelt to have the US begin research in nuclear technology. In response, Roosevelt organized the Uranium Committee whose job was to study the possibility of using enriched Uranium to create an atomic bomb. Two years later in October of 1941 the National Defense Research Committee also began research on nuclear technology. Just a few months later the US declared war on Japan then Germany and Italy. The US needed more than just research in nuclear technology and in response the Manhattan Project was created in A