Germany’s invasion of Poland in 1939 launched World War II

The Nazis and Soviets agreed to a non‑aggression pact in 1939

On August 23, 1939, Nazi Germany and the Soviet Union signed the Molotov–Ribbentrop Pact—a public commitment to not attack each other combined with a secret agreement dividing Eastern Europe into spheres of influence. This pact enabled Germany to invade Poland unopposed from the east and delayed conflict with the USSR until June 1941.

Hitler declared war on the United States four days after Pearl Harbor

Despite having no treaty obligation to join Japan’s fight, Hitler declared war on the US on Dec. 11, 1941. The move pulled America into the European theater and is widely seen as one of Hitler’s most strategic blunders.

Hitler's 1941 invasion of the USSR doomed Nazi Germany

Hitler unleashed Operation Barbarossa on June 22, 1941, underestimating Soviet resilience, Russian winter, and logistics. His overconfidence—rooted in early victories like France—turned this campaign into a strategic catastrophe, shifting the war’s momentum irreversibly—often cited as his greatest blunder.

Germany’s surprise offensive in December 1944 failed to break Allied lines

In a bold counterattack from December 16, 1944, to January 28, 1945, Hitler committed over 400,000 troops in a surprise “Bulge” through the Ardennes forest in France. Although initially successful in creating a 50‑mile incursion, Allied defense halted the advance. German forces suffered irrecoverable losses (~100,000), while Allied casualties totaled ~75,000, marking the offensive as the last major German gamble and a decisive step toward Nazi defeat.

The “Phoney War” was an eight‑month build-up to war

From September 1939 to May 1940, following their war declaration on Germany, Britain and France entered a phase of military inaction—even as civil defence measures, naval blockades, and rationing intensified at home. Skirmishes were limited, but the decisive fighting didn't begin until Germany invaded Norway and France in April–May 1940, abruptly ending the uneasy stalemate.

Illustrating the beginning and end of WWI through maps

In August of 1914, Germany invaded an ostensibly neutral Belgium, kick-starting World War I. The war became one of the deadliest conflicts in human history, decimating Europe and reshaping global politics for the next century. It also brought forward sweeping and terrifying new military technologies, a product of the Industrial Revolution. Explore 40 maps explaining the Great War in detail.

How the Great Depression and end of WWI paved the way for Hitler’s rise to power

The end of WWI was triggered by an armistice that blamed the conflict on Germany and required the financially struggling country to pay reparations. This outraged nationalists and ignited conspiracies that Hitler was able to capitalize on, according to this six-minute video. It was during this financial strain that the Great Depression hit.

D-Day, history's largest amphibious invasion, turned the war's tide

On D‑Day, over 156,000 American, British, and Canadian troops assaulted five heavily defended beaches along a 50‑mile stretch of northern France. Supported by nearly 3 million men, 1,200 warships, and 13,000 aircraft, the successful landings paved the way for the liberation of Western Europe and decisively shifted momentum against Nazi Germany.

The Nazi Party was founded in Germany in 1920 and tried a failed coup in 1923

Founded in Germany in February 1920, the National Socialist German Workers’ Party (Nazi Party) attempted its first major power grab in 1923 with the Beer Hall Putsch—a failed coup in Munich that killed about 16 Nazis and four police officers, led to Hitler’s arrest and treason trial, but ultimately elevated his public profile.

Exploring Kristallnacht

Nov. 9 and 10, 1938, saw Nazi members break into Jewish stores and homes across Germany in retaliation for the assassination of a German diplomat by a Polish Jew. The event—called "Kristallnacht," meaning "night of the broken glass"—was tacitly condoned by the German authorities at the time. This richly produced interactive explores the events of Kristallnacht guided by one of its survivors, Charlotte Knobloch.

A 1980 Oktoberfest bombing killed 13 people

The event was the country's deadliest domestic terror attack since World War II, killing 13 people and injuring more than 200. The perpetrator was 21-year-old Gundolf Koehler, who hoped to use the attack to usher in a conservative chancellor.

When German submarines lurked in US coastal waters

During World War II, German submarines (also known as U-boats) prowled the Southern coast of the US in 1942 and 1943, sinking more than 60 ships and killing 600 Allied soldiers. The campaign is less well-known, since the major battles in Stalingrad and Midway happened at the time. Several of these submarines and the ships they sank are now popular diving spots.

How World War II affects your wallet today

The world's deadliest conflict also impacted social programs extensively, including ways that still affect your money today. World War II is responsible for the practice of employers withholding tax payments and sponsoring health insurance, as well as the norm of providing school lunches for the nation's schoolchildren. Watch this brief video to learn more.

Japan committed mass war crimes during its invasion of China

During the 1937 invasion, Japanese forces carried out systematic atrocities—including mass executions, rape, torture, forced labor, and chemical warfare. The Nanjing Massacre alone killed tens of thousands over a span of six weeks, with some estimates claiming 300,000.

Wojtek the bear fought for Poland in World War II

Wojtek was a Syrian brown bear who eventually became a mascot, symbol, and eventually a soldier attached to the Polish II Corps during World War II. Learn about the amazing Wojtek, the Polish II Corps, and the incredible history of the Polish soldiers, many of whom had been imprisoned by the Germans or Soviets, who served during World War II.

Manhattan Project explained

Driven by fears of a Nazi nuclear bomb, the Manhattan Project united leading scientists to build the first atomic weapons. Its success ended World War II, caused catastrophic human loss, and launched the nuclear age that reshaped global politics and science.

The Night Witches

During World War II, one of the most effective Soviet bombing units flew wooden crop dusters that maxed out at 94 mph. They had no radios, no radar, and no parachutes. And the pilots? Young Soviet women, mostly in their teens and early twenties. The Germans called them Nachthexen—Night Witches. Shooting one down earned a Nazi soldier an Iron Cross, one of the highest military honors. However, for decades, most of the world forgot they existed. In this video, we trace how the Night Witches became one of the most feared units of WWII—and why their story nearly disappeared from history.

The Partitions of Poland led to the erasure of the Polish-Lithuanian Commonwealth

Political instability and foreign interference weakened the Commonwealth, which was eventually divided between Prussia, Austria, and Russia. Poland would not be re-established until after World War I and decades of imperial oppression.

Poland spends the most on NATO (as a share of GDP) at 4.1%, as of 2024

BBC explores how much each NATO member spends on defense and includes a helpful map displaying the defense spending of European countries as a percentage of GDP.

Can you save Britain from the Nazis by carefully sharing secrets with America?

Find out in this 20-minute interactive graphic novel based on true events from World War II.

Picasso's 'Guernica' protested the bombing of a Basque village

By 1937, Picasso's fame and influence had already made him a legend. Yet an unprovoked war crime in Guernica, Spain that same year—where 25 bombers dropped 100,000 pounds of bombs and explosives on civilians—inspired one of his most moving works.

After World War II, pizza took off in the US

Pizzerias opened in cities throughout the 1920s and '30s, especially those with large Italian immigrant populations, but the cuisine didn't take off nationally until after World War II. Some credit that with American soldiers' exposure to the food while stationed in Italy; others point to the invention of the mass-produced gas-fired ovens, which made opening a pizzeria considerably easier. Below is a 1944 clip from the New York Times, the first time the paper mentioned pizza.

The 20th-century rise of fascism affected the World Cup

Spain, in the midst of a civil war, did not participate, and Japan, after invading China, pulled out of the competition. An additional six Central and North American teams scratched by the time that year's World Cup began.

Penicillin slashed battlefield pneumonia deaths during World War II

Before antibiotics, bacterial pneumonia killed about 18% of infected soldiers in World War I. By World War II, penicillin cut that death rate to less than 1%.

A short history of space exploration

Let us to take you back through the timeline of space exploration and its rich, fascinating history, starting in 1946, with a rudimentary German military rocket.

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in casualties, forces mobilized, and displacement of civilians.

American dance legend Martha Graham, sometimes called 'the Picasso of dance,' refused to perform at the 1936 Olympics in Berlin and conceived the piece 'Chronicle' in response to the experience.

In 1915, workers recovered a submarine-like vessel from the Chicago River, prompting fears of German espionage

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

In 1984, Operation Smash Hit intentionally crashed a 239-ton train into a nuclear waste canister at 100 miles per hour to prove the canister's safety, which remained completely intact and lost just 0.29 of its 100 pounds of pressure.

Dorothy's famous entrance into Oz in 'The Wizard of Oz' relied on analog tricks, including a body double and sepia-toned paint, as much as it did on technology

Learn more about the history of fireworks, which dates back to an accidental invention during an alchemist's quest for information about immortality.

View the ten deadliest tornadoes in US history.

Waves off the coast of Nazaré, Portugal, can reach over 100 feet and are caused by the area's deep underwater canyon geography

See the most iconic photos from four decades of LIFE magazine

The US first hosted the World Cup in 1994, a tournament that lives in soccer infamy for its poor planning and the murder of Colombian player Andres Escobar, who'd accidentally scored on his own net.

A 2019 Facebook event called on attendees to "Storm Area 51, They Can't Stop All of Us," resulting in countless memes, the creation of a music festival, and eventually the arrests of those who did try to approach the area.

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

A pickleball's loud 'pop' sound can reach 120 decibels, which is equivalent to a hammer hitting a nail

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

One disco producer saw 'Star Wars' four times on its opening weekend and was so inspired that he recorded the album 'Star Wars and Other Intergalactic Funk,' which produced a chart-topping single.

About 12.5% of US adults experience a phobia in their lifetime, a diagnosis that hinges on the intense fear interfering with daily life and persisting for at least six months.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

Electrical grids worldwide must double their power delivery capacity by 2050 to meet surging demand from AI and electric vehicles.

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

Meet the 56 signers of the Declaration of Independence—most of whom didn't put pen to paper until August 2, 1776—and see their original signatures.

An initial public offering or 'IPO' is the process of a private company becoming public by putting shares of the company on the stock market for purchase.

The most expensive ad of all time was for Chanel No. 5 perfume and cost roughly $33M to produce in 2004—about $57M in today's dollars.