- German dictator Adolf Hitler invades Norway, Denmark, the Netherlands , Belgium, Luxembourg, and then France. He devastates opposing forces with "blitzkrieg," a strategy that stresses surprise, speed, and overwhelming force using air planes and mechanized ground forces. The USSR annexes Estonia, Latvia, and Lithuania. Winston Churchill becomes Prime Minister of Great Britain and vows Britain will never surrender. The German Luftwaffe far outnumber the Royal Air Force (RAF) as Hitler bombs London for months.
- The US government publicly opposes Hitler's aggression in Europe but refuses to get involved. President Roosevelt says he will not send troops into any foreign wars. The government promotes hemispheric defense through a Good Neighbor Policy in Latin America. The dictators of Germany, Japan and Italy join forces. The US advocates peace but starts supplying Britain aid to help that country defend itself.
- High unemployment carries over from the Great Depression, but agriculture and industry begin to rebound. Normal rainfall returns and farmers harvest a big crop of corn, wheat, soybeans, and other crops. Production increases and prices rise. European countries are cut off by German blockades, so exports go down, but America's demand for agricultural goods goes up. The Social Security Administration, created by 1930s New Deal legislation, sends out its first checks. Banking and credit industries become stronger after the 1930s.
- Congress passes several laws related to national defense, including the Selective Training and Service Act of 1940, which provides drafting and training men for the army and navy, marines and national guard. More than 16 million men register for the draft, which also allows for conscientious objectors to be employed in non-combat work. Congress authorizes money to build planes and ships, housing for soldiers, and establishes new military bases across the country. The Alien Registration Act requires that all aliens register with the government.
- Scientists learn that plasma can be substituted for whole blood transfusions; the Rh factor of blood is discovered. Food is freeze dried for the first time.
- CBS demonstrates the first color television in New York City, and WNBT in New York City becomes the country's first regular television station, broadcasting to about 10,000 viewers.
- Transportation expands. The first multi-lane superhighway, the Pennsylvania Turnpike opens; and the first Los Angeles freeway opens. Burma Shave roadside ads are set up along the highways, and the first MacDonald's hamburger stand opens in Pasadena, California.
- People enjoy an array of popular books, movies and dances. The Grapes of Wrath by John Steinbeck is popular, and the movie Gone with the Wind wins an Academy Award. Walt Disney releases "Pinocchio" and "Fantasia." Other movies include "The Great Dictator," "The Philadelphia Story," and "The Grapes of Wrath," staring former Nebraskan Henry Fonda. Americans enjoy "Bugs Bunny" cartoons and hear the "Superman" radio show for the first time. Big band music is popular and the Swing Era is in full swing.
- Following the 1940 election, Franklin Roosevelt is inaugurated for a third term as president and urges that the US become an arsenal of democracy. Iowan Henry Wallace is vice president. The Lend-Lease Act gives the President power to sell or lend war supplies to other countries. Roosevelt sends emergency food aid to the Soviet Union.
- US General Leslie R. Groves is appointed to direct the Manhattan Project, a top secret effort to build an atomic weapon before Germany or Japan. General Groves starts engineering and production centers at Los Alamos, New Mexico, directed by physicist J. Robert Oppenheimer; Oak Ridge, Tennessee; and at the Hanford Engineer Works in eastern Washington. At the University of Chicago, physicist Enrico Fermi, who had fled the Fascist regime in Italy, supervised related experiments. Under university's football stadium stands in 1942, the first self-sustaining nuclear reaction occurs. At Los Alamos a team of international engineers and scientists races to create atomic weapons for the US.
- In Europe, Germany forces 5,000 Jewish people in Paris to labor camps and isolates Jews in Warsaw, Poland, into a walled ghetto. Jews are prohibited from appearing in public without wearing a star and they cannot leave residential areas without police permission. Hitler ignores the German-Soviet nonaggression pact and invades the Soviet Union. Slowed by the bitter Russian winter, the German war machine fails to conquer Moscow.
- The Japanese attack the US base at Pearl Harbor on Sunday, December 7, 1941. In the surprise attack, more than 350 Japanese airplanes sink 12 US ships and destroy or damage more than 300 aircraft. More than 2,300 military personnel are killed and 1,100 wounded. More than 1,100 men on the battleship Arizona die and the ship sinks. The Japanese attack nearby Hickam Air Field and destroy nearly 20 bombers and fighters. A few US fighters manage to get into the air during the attack. Twenty-nine Japanese aircraft are shot down by US pilots and by ground fire. The next day, President Roosevelt says that December 7, 1941 is date which "will live in infamy" and declares war against Japan. Japan's allies Italy and Germany declare war on the US.
- A presidential warrant gives the US attorney general power to have the FBI arrest dangerous enemy aliens, including German, Italian and Japanese nationals. Within weeks, more than 1,300 people are detained.
- The United Service Organizations (USO) is started. The USO provides recreation for armed forces personnel. During World War II, more than 730,000 volunteers operate more than 3,000 recreational clubs wherever they could find space in churches, museums, barns, railroad cars, or stores. The USO gives soldiers a place to talk, dance, see movies, or write letters home. Bob Hope is the most famous member of touring USO shows. During his career, he brought laughter to millions of homesick soldiers fighting in World War II, the Korean War and the Vietnam War.
- Popular movies this year: "Citizen Kane," "How Green was My Valley," "Sergeant York," "The Maltese Falcon," "Dumbo." Popular comic book characters: Wonder Woman, Superman, Batman, Pogo, and Sad Sack. The year's most popular song is "Chattanooga Choo Choo" by Glenn Miller, who spent time as a child in North Platte, Nebraska. New York Yankees center fielder Joe DiMaggio sets a record with hits in 56 consecutive games, and baseball legend Lou Gehrig dies of the disease that today bears his name. One of the first World War II patriotic songs is "Remember Pearl Harbor," soon followed by "Praise the Lord and Pass the Ammunition."
- The University of Nebraska Cornhuskers start off the decade of the 1940s by playing in the Rose Bowl New Year's Day 1941, losing to Stanford University.
- Nazi leaders call a conference to coordinate the final solution to the Jewish question what comes to be known as The Holocaust, the systematic genocide of Jews and other minorities that do not fall within Hitler's concept of a master Aryan race.
- More than 120,000 Japanese Americans (Nisei) living on the West Coast are moved inland to internment camps, some for the duration of the war. Although most were born in this country, the Nisei are designated enemy aliens who must obey travel restrictions, curfew, and contraband regulations. Many lose their homes, farms and property during this time of internment.
- President Roosevelt urges Americans to support the war effort, and the country shifts into a wartime economy. Industry accelerates production, automakers produce tanks and planes and new industries are created when items such as rubber are cut off by war in Asia. Employment jumps. Unions gain new members. Farmers prosper as yields and crop prices go up. The US creates the Office of War Information (OWI), which creates Uncle Sam wants you, posters. The OWI's goal is to inspire patriotism and attract workers to jobs fueling the war effort.
- Dozens of everyday items such as gasoline and sugar are rationed. At the end of 1941 the government halts the production of cars to save steel, glass and rubber for war industries. In 1942 the government stops manufacture of refrigerators, radios, sewing machines, vacuum cleaners, and phonographs.
- The work force changes as millions of men leave their jobs for military service. To fill the labor shortage, women work in factories, earning the nickname Rosie the Riveter. [LINK TO FAMILY LIFE/WOMEN] Hundreds of thousands of African Americans leave farms in the South to take defense-related factory jobs in the North. Prison inmates help harvest beets and potatoes in western states. Nearly 400,000 Mexican Americans serve in the military during the war; others work in industry. To meet the demand for field workers, the US establishes the work hands program; thousands of Mexican immigrants come to farms in the Southwest to work.
- Radar is put to general use. The first nuclear reactor was built. The first electronic digital computer is built in Iowa. The 1,522-mile Alcan Highway opens, connecting Dawson Creek, British Columbia with Fairbanks, Alaska. The concern about a Japanese invasion through Alaska makes construction of the Alcan a military priority. Thousands of US and Canadian soldiers build the highway in a little over eight months. They work through the heat, mosquitoes in the summer, and winter temperatures near 40 degrees below zero.
- "Casablanca" premieres in theatres about the same time the Allied Expeditionary Forces landed and started bombing the real Casablanca in Morocco, North Africa, an area occupied by the Nazis. Also at the movies: "Yankee Doodle Dandy," "Pride of the Yankees."
- The Allies try to stop German munitions and aircraft production centers by bombing key German cities. In Eastern Europe, 200,000 German troops surrender to Soviet forces after months of savage fighting and heavy losses on both sides. On the Pacific front, Japan conquers the Philippines, Malaysia, the Dutch East Indies and Burma. In the battles at Iwo Jima and Okinawa, US forces take heavy casualties. Even after a major defeat at the Battle of Midway in 1942, Japan refuses to surrender.
- The US Army activates the 442nd Regimental Combat Team made up of the 100th Battalion from Hawaii and Japanese American volunteers from mainland concentration camps. Nearly 10,000 Hawaiian Nisei volunteer for military service. The 100th Battalion fights in North Africa, Italy, France and Germany. They rescue the "lost battalion" in 1944 and liberate the survivors at the Dachau Nazi concentration camp.
- Americans continue their hard work, cooperation, and patriotism. Citizens buy war bonds and planted victory gardens to grow their own food. School enrollment goes down as teenagers took jobs or join the military. Families continue to cope with rationing and, in some areas, housing shortages. As cities grew with defense workers, house shortages added to racial tensions. A riot in a federally sponsored Detroit housing project left 35 blacks and 9 whites dead.
- The Pentagon in Washington D.C. is completed and becomes the largest office building in the world. President Roosevelt freezes prices, and wages to prevent inflation. Wage-earners have a 20 percent flat income tax taken out of their paychecks. Because copper is needed for war material, 1943 US pennies are made from steel and zinc. War industries boost the growth of cities as farm-dwellers move to the cities and work in defense industries.
- Selman Waksman discovers streptomycin and coins the term "antibiotic."
- The jitterbug is a hot dance craze. "Oklahoma" is a popular musical on stage, and people go to see "For Whom the Bell Tolls," "The Ox-Bow Incident" and "Desert Victory" at the movies. Frank Sinatra and Dinah Shore are America's most popular singers.
- At the University of Nebraska, football coach Biff Jones leaves for military service, as do many of the region's athletes. Like other schools, Nebraska fields some rag-tag teams during the war years. Tom "Train Wreck" Novak earns 1949 All-America honors on a team with a 4-5 record. In the 1940s Nebraska has a string of losing seasons that doesn't end until 1950.
- President Franklin Roosevelt is elected to a fourth term. The GI Bill of Rights is passed, providing a variety of benefits for military veterans. The Supreme Court rules that internment of Japanese Americans is constitutional.
- The morning of June 6, 1944, (known as D-Day) 3,000 warships carry 200,000 American and British soldiers cross the stormy English Channel and land on the heavily fortified beaches of Normandy, France, to begin a vicious battle with the German army. The Battle of the Bulge begins in December as Hitler musters 500,000 troops along the Allied front from southern Belgium into Luxembourg. In bitter cold, they push ahead 50 miles, creating a bulge in the Allied lines. By the end of January, 1945, more than 76,000 Americans have been killed, wounded or captured.
- Nearly one million men, women, and children in the Leningrad, Russia, die from starvation and cold during a two-and-a-half-year siege and blockade by German troops. In China, the war begins its seventh year and Japanese troops occupying China were given orders to make the land uninhabitable. In Japan, children are taken out of school to work in factories producing bombs and other war equipment.
- DDT is developed to wipe out lice, a carrier of typhus, a disease which is infecting soldiers. DNA is isolated by Oswald Avery. The Germans develop the V-2, the first missile.
- In 1946, the first digital computer is introduced at the Moore School of Electrical Engineering in Philadelphia. The machine is huge 30 by 60 feet and weighs 60,000 pounds. A little different than today's hand-held computers!
- Movies: "Going My Way," with Bing Crosby and Ingrid Bergman, "Gaslight," "Lifeboat," "Meet Me in St. Louis," and "The Fighting Lady." Favorite books include The Razor's Edge by Somerset Maugham and A Bell for Adano by John Hersey. NBC airs the first US television network newscast.
- In March, US General George Patton's Third Army crosses the Rhine River and invades Germany. Allied forces liberate Paris after four years of Nazi occupation. That same month, the US bombs Tokyo with incendiary bombs, creating a firestorm and killing 120,000 people in a few hours. black and Japanese American troops are among those who liberate concentration camps and expose German atrocities.
- On May 7, 1945, Germany surrenders. The war in Europe is over. As Germany falls, Adolf Hitler commits suicide.
- In the Pacific, the Philippine Islands are recaptured. Marines land at Iwo Jima. After 36 days of vicious fighting that kills 20,000 Japanese and 4,000 Americans, the Japanese retreat from the island.
- Women are in the workforce and in uniform. By 1945 more than 250,000 women serve in the Women's Army Corps (WACS), Army Nurses Corps, the Women Accepted for Voluntary Emergency Service (WAVES), the Navy Nurses Corps, the U.S. Marines, and the Coast Guard. Most servicewomen are nurses or replace men in non-combat roles. During the war, the marines excluded black Americans, the navy used them as servants, the army created separate black regiments.
- President Franklin Roosevelt dies of a brain hemorrhage, and Missouri native Harry S. Truman becomes president. After considering all options, Truman gives the order and on August 6, 1945, the US drops an atomic bomb on Hiroshima, Japan. In minutes, half of the city vanishes and about 200,000 people are killed or missing. Radiation reaches more than 100,000 people. On August 9, the US drops an atomic bomb on Nagasaki. In September, Japan surrenders unconditionally on board the USS Missouri.
- "Carousel" opens on Broadway in New York City. Big band swing and "zoot" suits become popular. Popular songs include music from "Carousel," "At Mail Call Today" by Gene Autry; "Aren't You Glad You're You" by Bing Crosby; and "This Heart of Mine," by Judy Garland, as well a songs by Nat King Cole and Frank Sinatra. Gwendolyn Brooks, F. Scott Fitzgerald, and John Steinbeck are popular authors. Richard Wright's book Black Boy has an impact on the awareness of racial discrimination in the US.
- Grand Rapids, Michigan, is the first US city to fluoridate its water supply, improving dental health for the entire community. Raymond Libby develops oral penicillin.
- By the time World War II was over, nearly 300,000 Americans had been killed. In all countries bout 55 million people lost their lives. And more civilians lost their lives than soldiers.
- After World War II, the US and the USSR emerged as world powers. Although they fought as allies during World War II, the relationship between the two nations and the two political systems (democracy and capitalism vs. Communism) entered a new era of mutual hostility and conflict. As the two superpowers launched plans to construct and control nuclear arms, the world entered the Cold War.
- The first meeting of the United Nation's general assembly is held in London. Winston Churchill gives a speech cautioning the world of the Soviet Union's expansion ambitions. He uses the term "Iron Curtain." Twelve Nazi leaders are sentenced to hang after war trials at Nuremberg, Germany.
- The 1945 War Brides Act allows foreign-born wives of US citizens who served in the US military to enter the US A year later, another law permits fiancés of American soldiers to enter the US legally
- Jukeboxes go into mass production. One-story, split-level houses, called ranch style homes, become a trend in post-war housing construction.
- Dr. Benjamin Spock writes a best-selling book called Baby and Child Care, the famous how-to book for parents. A nationwide telephone numbering plan begins. Soap operas air on television for the first time with "Faraway Hill." On Broadway, Irving Berlin's musical "Annie Get your Gun" is a hit. People read John Hersey's book Hiroshima and Robert Penn Warren's novel All the King's Men. At the movies, people see "The Best Years of Our Lives," a story about the readjustment families face when loved ones return from war. "The Yearling," "The Razor's Edge," and "It's a Wonderful Life" are also popular.
- George C. Marshall, Army chief of staff during World War II and US secretary of state from 1947-1949, developed the European Recovery Program, known as the Marshall Plan, designed to rebuild the devastated cities of Europe. The Marshall Plan was a $13 billion effort to boost European economies, as well as to halt the spread of Communism.
- Industry booms as the pent-up demand for big and small appliances, cars, farm equipment, radios, and other household items that had been rationed or had ceased production during the war. Innovations from war equipment make their way into consumer goods. Chuck Yeager breaks the sound barrier in an X-1 rocket-powered research plane. African-American Jackie Robinson joins the Brooklyn Dodgers and breaks the color barrier in baseball. The transistor and microwave oven are invented.
- Television grows. President Harry Truman's State of the Union address and the Baseball World Series are televised. "Meet the Press," television's longest running program begins. "Howdy Doody" begins its 13 years on television. With television programming comes the start of commercials. By the end of the year, America had 139 commercial broadcast TV stations, but there were only an estimated 9,000 households with televisions.
- Weather grabs the headlines as a blizzard drops 70 inches of snow in New England and 170 people die and 10,000 homes are destroyed in a series of tornadoes in Texas and Oklahoma. A freighter carrying nitrate sets off an explosion at the Monsanto chemical plant in Texas City, Texas. The tragedy destroys the entire city. More than 500 people are killed, 2,100 injured.
- The musical "Brigadoon" and the play "A Streetcar Named Desire" launch on Broadway. Anne Frank's Diary of a Young Girl is published. At the movies: "Gentlemen's Agreement," "Miracle on 34th Street," "The Farmer's Daughter," "The Egg and I."
- People across the country become fascinated by the reports of flying saucers (unidentified flying objects, UFOs) during the summer. The government confirms to a New Mexico newspaper that a flying saucer has crashed near Roswell and alien bodies were recovered from the site; but the source later cancels all accounts of the crash, saying the object was a government weather balloon.
- The Soviet Union blockades Berlin, Germany, trying to force the Allies out of West Berlin. The Allies respond with a huge effort to supply the 2 million residents of West Berlin by airdrop. From June 1948 through September, 1949, huge cargo planes bring in more than 2 million tons of frozen American beef, flour, sugar, dehydrated foods, soap and medical supplies, newspapers, coal for fuel and equipment. The pilots also bring in candy for children. Food and supplies are packaged at the US Army Transport Terminal in Bremerhaven, Germany. By the end of the airlift, pilots log more than 277,000 flights.
- By executive order, President Harry Truman abolishes racial segregation in the US armed forces. The government upheld segregation during World War II, creating the first all-black military aviation program at the Tuskegee Institute in Alabama. The 99th Fighter Squadron fights battles in North Africa, Sicily and Anzio and was joined by three all-Black squadrons. Together, they are known as the 332nd Fighter group and come home with 150 medals.
- The Displaced Persons Act permits people from Europe who were displaced by the war to enter the US outside of existing immigration quotas.
- A group of movie and television writers, producers, and directors are called as witnesses by the House Un-American Activities Committee. The group is put in jail for contempt of Congress when they refuse to state if they are or are not Communists.
- "The Ed Sullivan Show" premieres on television. People are reading The Naked and the Dead; The Age of Anxiety; Cry, the Beloved Country; and Intruder in the Dust. Leo Fender invents the electric guitar. Western Union manufactures Deskfax machines. "Kiss Me Kate," is on Broadway. "The Treasure of the Sierra Madre," "Johnny Belinda," "The Snake Pit," and "Red River" are at the movies. Baseball player Babe Ruth dies soon after the release of the movie "The Babe Ruth Story." The Polaroid camera develops pictures in one minute, and the Bic ballpoint pen is on the market. Long playing (LP) records (25 minutes per side) are introduced.
- The US joins in forming the North Atlantic Treaty Organization (NATO), a pact for mutual defense of Belgium, Britain, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, and the US. The USSR's leader Joseph Stalin signs an alliance with the People's Republic of China, a Communist nation formed in 1949. The Soviet Union conducts its first atomic test.
- Germany is split into the German Democratic Republic (East Germany under Soviet Communist rule and the Federal Republic of Germany (West Germany).
- The US Air Force begins Operation Haylift, an emergency effort to get food to 2 million cattle and sheep stranded by heavy snow on the Great Plains.
- The musicals "South Pacific" and "Gentlemen Prefer Blondes" and the play "Death of Salesman" are popular. Influential books include: The Second Sex, presenting the idea of male oppression of women; 1984, describing a bleak, fascist future; and Norman Vincent Peale's upbeat Guide to Confident Living. RCA markets 45 rpm records and record player. Milton Berle hosts the first telethon, and the Emmy Awards for television begin. Movies: "Twelve O'Clock High," "Sands of Iwo Jima," "Battleground," and "The Third Man."
- The popularity of big band music declines. A faster style based on improvisation, called bebop or bop, emerges. Popular jazz musicians are saxophonist Charlie Parker, trumpeter Miles Davis, pianist Earl Powell, drummer Max Roach, pianist-composer Thelonious Monk, and composer-arranger Gil Evans. Modern jazz bands led by Dizzy Gillespie and Stan Kenton are popular.