World War II, or the Second World War, was a global military conflict, the joining of what had initially been two separate conflicts. The first began in Asia in 1937 as the Second Sino-Japanese War; the other began in Europe in 1939 with the German invasion of Poland.
This global conflict split the majority of the world's nations into two opposing military alliances: the Allies and the Axis powers. It involved the mobilization of over 100 million military personnel, making it the most widespread war in history, and placed the participants in a state of "total war", erasing the distinction between civil and military resources. This resulted in the complete activation of a nation's economic, industrial, and scientific capabilities for the purposes of the war effort. Over 60 million people, the majority of them civilians, were killed, making it the deadliest conflict in human history. The financial cost of the war is estimated at about a trillion 1944 U.S. dollars worldwide, making it the most costly war in capital as well as lives.
The Allies were victorious, and, as a result, the United States and Soviet Union emerged as the world's two leading superpowers.
During this conflict 464 United States military personnel received the Medal of Honor, 266 of them posthumously. Additionally, the only recipient for the United States Coast Guard received the Medal for his actions during this war.
The Medal of Honor was created during the American Civil War and is the highest military decoration presented by the United States government to a member of its armed forces. The recipient must have distinguished themselves at the risk of their own life above and beyond the call of duty in action against an enemy of the United States. Due to the nature of this medal, it is commonly presented posthumously