Humanities › History & Culture The War Years: A Timeline of the 1940s Share Flipboard Email Print ThoughtCo / Evan Polenghi History & Culture Inventions Invention Timelines Famous Inventions Famous Inventors Patents & Trademarks Computers & The Internet American History African American History African History Ancient History and Culture Asian History European History Genealogy Latin American History Medieval & Renaissance History Military History The 20th Century Women's History View More By Jennifer Rosenberg History Expert B.A., History, University of California at Davis Jennifer Rosenberg is a historian and writer who specializes in 20th-century history. our editorial process Jennifer Rosenberg Updated March 16, 2020 The 1940s tower over every other decade of the 20th century as the most full of sorrow, patriotism, and ultimately, hope and the beginning of a new era of American dominance on the world stage. This decade, commonly called "the war years," is synonymous with World War II. This decade left an indelible mark on all but the youngest of Americans that lasted for the rest of their lives. Those who were young and in the military were dubbed "The Greatest Generation" by former NBC News anchor Tom Brokaw, and the moniker stuck. Adolf Hitler's Nazi Germany invaded Poland in September 1939, and the war dominated Europe from that moment until the Nazis surrendered. The United States was drawn into World War II with the Japanese bombing of Pearl Harbor in December 1941 and was then involved in both the European and Pacific theaters until peace came in May 1945 in Europe and August of that year in the Pacific. 1:58 Watch Now: A Brief History of the 1940s 1940 Massimo Pizzotti / Getty Images The first year of the 1940s was filled with war-related news. In 1940 or late 1939, the Nazis began "Operation T4," the first mass killings of Germans and Austrians with disabilities, most by large-scale poison gas operations. This program alone resulted in the murder of an estimated 275,000 persons by war's end. May: The Germans opened the Auschwitz concentration camp, where at least 1.1 million people would be killed. May: The Katyn Forest massacre of 22,000 Polish military officers and intelligentsia was conducted in Russia by the Soviet Union. May 14: After years of experimentation and investment, stockings made of nylon rather than silk hit the market because silk was needed for the war effort. May 26–June 4: Britain was forced to retreat from France in the Dunkirk evacuation. July 10–October 31: The Battle of Britain raged with Nazi bombings of military bases and London, known as the Blitz. Britain's Royal Air Force was ultimately victorious in its defense of the U.K. July 27: Warner Brothers' signature cartoon rabbit Bugs Bunny debuts in "A Wild Hare," co-starring Elmer Fudd. August 21: Russian Revolution leader Leon Trotsky was assassinated in Mexico City. September 12: The entrance to Lascaux Cave, containing Stone Age paintings dated to 15,000–17,000 years old, was discovered by three French teenagers. October: The Warsaw Ghetto, the largest of the Jewish ghettos opened by the Nazi, was established in Poland, and would eventually house as many as 460,000 Jews there in an area of 1.3 square miles. November 5: President Franklin D. Roosevelt was elected to an unprecedented third term. 1941 Underwood Archives / Getty Images By far the biggest event for Americans in 1941 was the Japanese attack on Pearl Harbor on Dec. 7, 1941, a day that would indeed, as FDR said, live in infamy. March: The quintessential superhero "Captain America" made his debut in Marvel Comics. March 3: Forrest Mars, Sr. obtained a patent for the candy to be known as M&M's and based on British-made Smarties. May 1: Cheerios cereal, or rather CheeriOats as it was known then, was introduced. May 15: Joe DiMaggio began his 56-game hitting streak, which would end on July 17, with a batting average of .408, 15 home runs, and 55 RBIs. May 19: Chinese leader Ho Chi Minh founded the Communist Viet Minh in Vietnam, an event that was to lead to yet another war for the U.S. years later. May 24: The British battle-cruiser HMS Hood was sunk by the Bismarck during the Battle of Denmark Strait; the Royal Navy sunk the Bismarck three days later. June 22–December 5: Operation Barbarossa, an Axis invasion of the Soviet Union, took place. The plan was to conquer the western Soviet Union and repopulate it with Germans; and in the process, the German armies captured some five million troops and starved or otherwise killed 3.3 million prisoners of war. Despite the horrific bloodshed, the operation failed. August 14: The Atlantic Charter was signed, setting out goals for England and the U.S. after the close of World War II. It was one of the basic documents underlying the modern United Nations. September 8: The Nazis began a prolonged military blockade known as the Siege of Leningrad, which would not end until 1944. September 29–30: In the Babi Yar Massacre, Nazis killed over 33,000 Jews from Kiev in a ravine in Ukraine; the killing would continue for months and involve at least 100,000 people. October 31: In South Dakota, Mount Rushmore, a sculpture of 60-foot-high faces of four U.S. presidents, was completed after 14 years under the direction of Gutzon Borglum. November: The first prototype of what would become the Jeep, the Willys Quad, was delivered to the U.S. Army. 1942 Anne Frank House In 1942, World War II continued to dominate the news. February 19: President Franklin D. Roosevelt signed an Executive Order commanding the relocation of Japanese Americans families from their homes and businesses to internment camps. April 9: At least 72,000 American and Filipino prisoners of war began a forced march by the Japanese 63 miles from the southern tip of the Bataan Peninsula to Camp O'Donnell in the Philippines. An estimated 7,000–10,000 soldiers died along the way in what became known as the Bataan Death March. June 3–7: The naval Battle of Midway occurred, between the U.S. Navy led by Admiral Chester Nimitz and the Imperial Japanese Navy led by Isoroku Yamamoto. The decisive win by the U.S. is considered a turning point in the Pacific theater. July 6: Anne Frank and her family went into hiding from the Nazis in an attic apartment behind her father's pectin-trading business in Amsterdam. July 13: The first printed T-shirt worn in a photograph appeared on the cover of Life magazine, a man brandishing an Air Corps Gunnery School logo. August 13: The Manhattan Project, a U.S. federally-funded effort to develop and produce nuclear weapons, began. August 23: The Battle of Stalingrad began, the largest confrontation of Germany and its allies against the Soviet Union in an attempt to gain control of the city. 1943 PhotoQuest / Getty Images April 13: The Germans announced that they had discovered 4,400 bodies of Polish officers in a mass grave in Russia's Katyn Forest, the first concrete evidence of the Katyn Massacre of May 1940. April 19: German troops and police entered the Warsaw Ghetto to deport its surviving inhabitants. The Jews refused to surrender, and the Germans ordered the burning of the ghetto, which lasted until May 16 and killed an estimated 13,000 people. July 8: French resistance leader Jean Pierre Moulin is said to have died on a train near Metz and headed to Germany after being tortured by the Nazis. October 13: One month after surrendering to Allied forces, the government of Italy under Pietro Badoglio joined the Allies and declared war on Germany. 1944 Keystone / Getty Images June 6, 1944 was momentous: D-Day, when the Allies landed in Normandy on the way to liberate Europe from the Nazis. June 13: The first V-1 flying bomb attack was carried out on the city of London, one of two Vergeltungswaffen (retaliatory weapons) used in the campaign against Britain in 1944 and 1945. July 20: German military officers led by Claus von Stauffenberg led Operation Valkyrie, a plot to kill German chancellor Adolf Hitler inside his Wolf's Lair field headquarters, but failed. 1945 CORBIS / Corbis / Getty Images World War II ended in Europe and the Pacific in 1945, and those two events dominated this year. January 17: Swedish diplomat Raoul Wallenberg, who saved tens of thousands of Jews in Nazi-occupied Hungary, disappeared in Budapest after being called to Soviet military commander Rodion Malinovsky's headquarters in Debrecen. He was never seen again. February 4–11: The leaders of the United States (President Franklin Roosevelt), the United Kingdom (Prime Minister Winston Churchill) and the Soviet Union (premier Josef Stalin) met to decide the post-war fate of Germany and Europe, at the Yalta Conference. February 13–15: British and American forces launched an aerial bombing attack on the city of Dresden, effectively destroying over 12,000 buildings in the city's old town and inner eastern suburbs. March 9–10: Operation Meetinghouse, in which the U.S. Army Air forces bombed the city of Tokyo, was conducted, only the first of firebombing raids against the city that would continue until the end of the war. April 12: U.S. President Franklin D. Roosevelt died at his Warm Springs, Georgia estate. His vice president Harry S. Truman took office. April 30: Adolf Hitler and his wife Eva Braun committed suicide by cyanide and pistol, in an underground bunker under his headquarters in Berlin. May 7: Germany signed the first legal German Institution of Surrender in Reims, although the final document was signed on May 9. August 6 and 8: The United States detonates two nuclear weapons above the cities of Hiroshima and Nagasaki, the first and (so far only) use of such a weapon against an enemy people. August 10–17: Korea is divided into North (occupied by the Soviet Union) and South (occupied by the United States). August 15: Emperor Hirohito announces the surrender of Japan, formally signed on September 2. October 8: Inventor Percy Spencer filed the first of what would be 150 patents for the Microwave oven, to be made available to the public as the Radarange. October 24: The United Nations was founded in San Francisco, California, by representatives of 50 countries. October 29: The Reynolds pen, an early ballpoint, went on sale in the U.S. It proved immensely popular, with several advantages over the fountain pen—a smooth ball bearing instead of a scratchy nib, and an instant-drying ink that only had to be refilled once every six months. November: The Slinky toy was demonstrated at Gimbel's department store in Philadelphia. November 20: The Nuremberg trials began, military tribunals prosecuting prominent members of the leadership of Nazi Germany for their crimes in World War II. 1946 Keystone / Getty Images With World War II over, the news lightened up considerably in 1946. February 15: ENIAC, the first electronic, general purpose digital computer, was announced to the public by the U.S. Army. February 24: Juan Perón was elected president of Argentina. March 5: Winston Churchill gave his "Iron Curtain" speech, condemning Soviet Union policies in Europe. July 1: Nuclear testing began in the Bikini Atoll, Marshall Islands, the first of 23 detonations by the United States between 1946 and 1958. July 4: The post-Holocaust outbreak of violence known as the Kielce Pogrom in Poland was conducted by Polish soldiers, police officers and civilians who killed between 38 and 42 people. July 5: Bikini swimsuits made their debut on a Paris beach but quickly spread to beaches everywhere. July 14: Dr. Spock's "The Common Book of Baby and Child Care" was published, just in time for the start of the post-war Baby Boom. July 22: The militant right-wing Zionist organization known as the Irgun bombed the King David Hotel in Jerusalem, killing 91 people. December 11: UNICEF, the United Nations Children's Fund, was founded in New York City. December 20: The landmark holiday movie "It's a Wonderful Life" had its premiere; it opened to mixed reviews. December 26: Las Vegas began its transformation into the gambling capital of the U.S. with the opening of the Flamingo Hotel. 1947 Bettmann / Contributor / Getty Images Sometime in 1947, the first of the Dead Sea Scrolls, a collection of ancient Hebrew and Aramaic documents stored in caves on the northwestern shore of the Dead Sea, were discovered. February 21: Polaroid cameras were introduced at a meeting of the Optical Society of America in New York City, just in time for all those baby shots. April 15: Jackie Robinson joined the Brooklyn Dodgers, becoming the first African-American baseball player in the Major Leagues. June: U.S. Secretary of State George Marshall gave a paper at Harvard in which he spoke of an urgent need to help Europe rebuild and later that year, the Marshall Plan doing just that took effect. July 11: Jewish refugees from France attempting to reach Palestine aboard the Exodus were forcibly turned back by the British. October 14: World War II fighter pilot Chuck Yeager broke the sound barrier for the first time, flying in a a Bell X-1 experimental aircraft. 1948 Imagno / Getty Images After the Nationalist Party in South Africa won a majority of seats in the parliament, they established "practical apartheid" in the country, a white supremacist strategy that would last another four decades. January 30: The philosopher and leader of India Mahatma Gandhi was assassinated by an advocate of Hindu nationalism. March: British astronomer Fred Hoyle, appearing on a BBC radio program, described the current theory of how the universe began as "one big bang at a particular time in the remote past," making the notion accessible to the public imagination and even though he didn't at the time accept it. April 12: Despite headlines saying "Dewey Defeats Truman," Harry Truman was elected president. May 14: Jewish politician and diplomat David Ben-Gurion announced the establishment of the State of Israel, and U.S. President Harry S. Truman quickly recognized the new nation. June 24: After the Soviet Union blocked Western Allies' routes into sections of Berlin in the Berlin Blockade, the U.S. and British organized the Berlin Airlift to bring supplies to West Berlin. 1949 The Print Collector / Print Collector / Getty Images April 4: The North Atlantic Treaty Organization (NATO) was established, an intergovernmental military alliance among 29 North American and European countries. March 2: The Boeing B-50 named Lucky Lady II landed at Carswell Air Force Base in Texas, completing the first non-stop flight around the world. It was refueled in the air four times. June 8: George Orwell's landmark "Nineteen Eighty-Four" was published. August 29: The Soviet Union conducted the first nuclear bomb test,in what is today Kazakhstan. October 1: After the Chinese Communist Revolution, part of the Chinese Civil War, leader and party chairman Mao Zedong proclaimed the creation of the People's Republic of China.