World War II was unquestionably the largest and most significant armed conflict in human history. While it may have officially begun when Adolf Hitler’s Germany invaded Poland on September 1, 1939, roots of conflict stemmed from the Paris Peace Conference of 1919 and the resulting Treaty of Versailles.
Placing the full blame for the First World War on Germany, the treaty demanded heavy war reparations from the country. Because of this, the government’s treasury was emptied of all precious metals, leading to the complete devaluation of Germany’s currency. In turn, the government printed large amounts of money, which then caused a state of hyperinflation.
Economic conditions worsened with the Great Depression, with six million Germans facing unemployment in the 1930s.  Most devastating in Germany, these circumstances existed in countries across Europe, allowing for extremist groups such as Fascists and Nazis to thrive. In particular, the victory of Benito Mussolini’s Black Shirts in Italy in October 1922 “introduced the world to Fascism, which reinterpreted nationalism in totalitarian terms.” 
Taking Mussolini’s cue, Hitler’s National Socialist German Worker’s Party rose to power in 1933 with its promise of a “New Germany.” Claiming concern for the ethnic Germans within Czechoslovakia, Hitler managed to annex Sudetenland after the infamous Munich Conference in September 1938. This policy of appeasement, spearheaded by Britain’s Prime Minister Neville Chamberlain, proved to be a dire mistake as it fueled the fire of Hitler’s ambition.
With the loss of Sudetenland, Czechoslovakia was left too weak to resist the German occupation that followed. Shortly thereafter, the war commenced. In Asia, though the stage was set for war after Japanese troops marched into Manchuria in 1931, launching the first in a series of conquests and invasions in the 1930s, it was German aggression that truly encouraged an expansion of Japanese ambition. 
Throughout the war, there were an estimated 50 million military and civilian lives lost, with 19 million resulting from combat alone.
Among these, the Soviet death toll was reportedly anywhere between 10 and 27 million, with 3.5 million German losses, 2 million Chinese, 1.5 million Japanese, and less than 500,000 British and Americans. 
Whereas the United States served as the main provider of goods to the Allies in the midst of the war, the Soviet Union’s Red Army played the primary role in defeating Nazi Germany, inflicting 80 percent of the casualties against the Wehrmacht â€“ though with severe losses of their own.
While Germany and the Soviet Union had signed a Non-Aggression Pact on August 23, 1939 and had initially invaded Poland together, the shaky alliance quickly dissolved when Hitler invaded Russia on June 22, 1941. Fortunately, the Red Army refused to break and German tanks were slowed by the autumn mud and eventually immobilized by the winter snow.
The Nazis reached the outskirts of Moscow by December of that year but were unable to advance any further. In 1943, Hitler planned yet another assault on the Soviets surrounding the city of Kursk. In one of history’s biggest tank battles, “German panzers were stopped, then forced into a retreat that ended only in the streets of Berlin.”  It was here, encircled by Soviets, that Hitler eventually committed suicide in his bunker on April 30, 1945.
During his time as Chancellor of Germany and leader of the Nazi party in World War II, Hitler and his allies carried out a number of atrocities against a great many groups of people. The combination of a conspiracy theory that detailed a Jewish takeover and Hitler’s belief in a superior Aryan race led to the deaths of millions.
On the night of November 9, 1938 Hitler’s Stormtroopers ran amok, murdering and capturing Jews, ransacking, damaging, or destroying Jewish buildings and businesses, and burning down synagogues, in what became to be known as Kristallnacht.
Eventually, Jews, Soviet prisoners of war (POWs), Gypsies, homosexuals, handicapped persons, and political prisoners were starved, forced to work and live in labor or concentration camps, experimented on, and massacred. In a massive campaign of genocide that “included the ‘Final Solution,’ whereby 6 million Jews were killed,” Hitler slaughtered 15.5 million. 
Following the war, the Jews who managed to survive the cruelty of the Holocaust found themselves nationless. In an attempt to provide them a safe-haven, the newly formed United Nations (that was meant to replace the failed League of Nations) voted on the formation of a Jewish State. Thus, on “the day in which the British Mandate over a Palestine expired, the Jewish People’s Council gathered at the Tel Aviv Museum… and [declared] the establishment of the State of Israel” on May 14, 1948. 
Finally, the end of the war came with the Japanese surrender to the United States on September 2, 1945, after the nuclear bombings of Hiroshima and Nagasaki. These nuclear capabilities, coupled with disagreement about the future of Europe, jumpstarted a Cold War that would exist between the Soviet Union and the United States until the early 1990s.
 “The European Economy in the Interwar Period,” in 7.1.1: Social and Political Impact of World War I, 7.1: The Interwar Years, 1918-1938, Unit 7: The Rise of Totalitarian States in the 20th Century, HIST 103: World History in the Early Modern and Modern Eras (1600-Present) (Washington, D.C.: Saylor Foundation, 2014), https://learn.saylor.org/course/view.php?id=31§ionid=8816#section-86
 Judson Knight, “World War II,” in Encyclopedia of Espionage, Intelligence and Security, edited by K. Lee Lerner and Brenda Wilmoth Lerner, Vol 3 (Detroit: Gale, 2004): 275-282.
 Fred H. Lawson, “World War II,” in Oxford Encyclopedia of the Modern World, edited by Peter N. Stearns (Oxford: Oxford University Press, 2008).
 “Declaration of Establishment of State of Israel: 14 May 1948,” Israel Ministry of Foreign Affairs, http://www.mfa.gov.il/mfa/foreignpolicy/peace/guide/pages/declaration%20of%20establishment%20of%20state%20of%20israel.aspx