US intelligence warned in multiple reports of al-Qaida's plans to strike before 9/11.

al-Qaida targeted multiple US interests in attacks before 9/11

Before 9/11, al-Qaeda carried out several deadly attacks on US targets—including the 1998 embassy bombings in Kenya and Tanzania and the 2000 bombing of the USS Cole—killing hundreds of people.

Osama bin Laden declared jihad—a call for armed struggle framed as a religious duty—against the US in 1996.

9/11 reshaped US foreign and military policy for decades, shifting focus to non-state actors and the Middle East.

US intelligence failures contributed to the success of the Japanese attack

Despite breaking Japan’s diplomatic codes, US agencies failed to integrate warnings, successfully track Japan’s carriers, or even believe a Hawaii strike was possible (they also had not cracked Japan’s naval codes). Missed signals, ignored reports and poor coordination led to one of the worst intelligence failures in US history.

Experience 9/11, the deadliest terrorist attack on American soil, as it happened.

Decades of instability in the Middle East gave rise to al-Qaida.

President Bush addressed the nation on 9/11 from the Oval Office, watched by an estimated 80 million people.

al-Qaida was founded in 1988 by Osama bin Laden

The group emerged in 1988 from the militant networks formed during the Soviet-Afghan War. Under Osama bin Laden's leadership, it combined jihadist ideology with global ambitions—eventually orchestrating attacks across Africa, the Middle East, Europe, and the United States.

The US launched the Global War on Terror after 9/11

In the wake of 9/11, the US declared a Global War on Terror—initiating military operations in Afghanistan and Iraq, expanding surveillance, and forming international coalitions to combat terrorism and disrupt extremist networks worldwide.

9/11 permanently changed air travel security in the US with the creation of the Transportation Security Administration.

The Taliban provided al-Qaida with a safe haven in Afghanistan before 9/11 and returned to power in 2021

A fundamentalist Islamist movement, the Taliban ruled most of Afghanistan before 9/11, providing al-Qaida with training grounds and sanctuary. After 20 years of war, it regained power following the U.S. withdrawal in 2021.

One hijacked plane struck the Pentagon on 9/11, killing 125 people inside

American Airlines Flight 77 crashed into the Pentagon's west side, destroying a section of the building and killing all 59 on board, along with 125 military and civilian personnel, making it the deadliest attack on the US military headquarters.

Palantir's software is widely speculated to have enabled Osama bin Laden's assassination

While Palantir has never publicly confirmed the use of its software in the 2011 assassination, its technology is widely speculated to have been a critical aspect of the operation. However, Palantir executives have never denied the claim, either, and have frequently commented on the software's important role in defending Western civilizations from terrorism.

US intelligence allegedly pursued more than 600 schemes to assassinate Fidel Castro

From exploding cigars and poisoned Cohibas to an infected scuba suit and plans to drug a TV studio with LSD, this account catalogs the CIA's strangest—and consistently unsuccessful—attempts to kill Fidel Castro over decades.

How NATO responded to 9/11

The collective defense clause of the NATO constitution has only been invoked one time: after the 9/11 terrorist attacks against the United States. This video explores the immediate actions NATO took to respond to the attacks to support the United States. These firsthand clips from 2001 give a sense of the magnitude of the moment and the difficult decisions facing NATO leaders at the time.

The 2001 Authorization for Use of Military Force has been used by five administrations to justify military operations in at least 22 countries.

President George W. Bush learned of the 9/11 attacks while visiting a classroom.

The PATRIOT Act expanded government surveillance after 9/11

Signed into law weeks after the attacks, the PATRIOT Act granted federal agencies sweeping powers to monitor communications, access records, and conduct surveillance—sparking ongoing debates over privacy, civil liberties, and national security.

An NSA analyst helped avert nuclear war during the Cuban Missile Crisis

In October 1962, NSA cryptographer Juanita Moody headed analysis of U‑2 surveillance data and urgently produced intelligence on Soviet missile deployments in Cuba. Her reports drove high-level US decision-making, and were critical to avoiding nuclear war during the Cuban Missile Crisis.

The US and allies invaded Iraq based on flawed intelligence about potential weapons of mass destruction.

Flight 93 passengers fought back and prevented a fourth target

United Airlines Flight 93 was hijacked en route to Washington, DC. Passengers learned of the other attacks and stormed the cockpit. The plane crashed in Pennsylvania, likely preventing a strike on the US Capitol.

The War on Terror used controversial tactics like torture and secret prisons

As part of its post-9/11 strategy, the US employed enhanced interrogation, extraordinary rendition, and secret CIA black sites—practices widely criticized as torture and violations of international law and human rights.

Burglars accessed the DNC once before their failed June 17 attempt

Long before the notorious June 17 intrusion, the burglars successfully accessed and planted listening devices in the DNC offices on May 28—showing how deeply premeditated the operation was and how the scandal's roots stretched back well before the arrests.

The attack at Pearl Harbor required nearly a year of planning and preparation

In early 1941, Admiral Isoroku Yamamoto ordered detailed planning for a surprise carrier strike on Pearl Harbor. Japanese teams spent months refining torpedo modifications, training pilots, and rehearsing the complex attack.

The Soviet-Afghan War empowered militant jihadist networks

US and Pakistani support for Afghan mujahideen in the 1980s inadvertently built the infrastructure—training camps, ideology, and global fighters—that later evolved into al-Qaeda's foundation.

Coverage of the 9/11 terrorist attacks helped shape Wikipedia's editorial policies

Launched nine months earlier, the site was featured on Yahoo's news page, attracting traffic from information seekers as dozens of new editors created hundreds of articles, including memorials, conspiracy theories, and donation and volunteer pages. Discussions between editors would begin establishing rules for handling breaking news events.

A fake vaccine campaign was used to locate Osama bin Laden, fueling vaccine distrust

As part of the intelligence operation to find bin Laden in Pakistan, the US Central Intelligence Agency recruited a Pakistani doctor who ran a fake hepatitis B vaccine campaign and obtained DNA samples from bin Laden. News of this fake campaign fueled further distrust of healthcare workers, attacks on them, and stymied efforts to vaccinate against polio in the region.

NATO's Article 5 has been invoked once—after 9/11

The article was invoked the day after the attacks and launched a series of NATO campaigns to fight global terrorism. This page includes excerpts from a speech by then-NATO Secretary General Jens Stoltenberg about the attacks and the organization’s response.

9/11 was the first global disaster watched in real time across the world

As the first plane struck at 8:46 a.m. ET, CNN's live feed broadcast images worldwide within minutes. An estimated 2 billion people watched the collapse of the Twin Towers live.

A movie helped make JFK assassination conspiracies widespread

Oliver Stone's film "JFK" (1991) imagined the 1963 assassination of President John F. Kennedy as the result of a conspiracy by US government agents. Before the film, this belief was not common, but it became widely adopted afterward. The film's impact contributed to the release of major CIA files in subsequent decades. (Some users may experience a paywall.)

After the 9/11 terrorist attacks, The Onion stuck with satire, defying what some were predicting was 'the death of irony.'

The CIA once tried to poison Fidel Castro's milkshake during the Cold War.

Read about Palantir's early days—from a Stanford University dorm to an investment from the CIA

Palantir was originally founded after the 9/11 attacks as a private-sector solution to the government's growing need for advanced intelligence. One of its earliest investors was In-Q-Tel, the CIA's non-profit venture capital firm.

Spikes in pizza orders near US government buildings are thought to be signs of international crises

Theorists have long believed that sudden increases in pizza deliveries near the Pentagon signal a major event is about to occur. Historical examples include the CIA ordering 21 pizzas the day before the beginning of the Gulf War, and another surge of deliveries before former President Bill Clinton's impeachment hearings. Citizens have since begun monitoring food orders in the area. See a tracker of Pentagon pizza orders here.

One Day in America series reveals the full timeline and human toll of 9/11

This National Geographic episode reconstructs the events of 9/11—highlighting the Pentagon attack, Flight 93 hijacking, South Tower collapse, and rescue efforts—offering a detailed, chronological account of how the day unfolded.

AP Photos: 20 images documenting the enormity of 9/11

The Associated Press shares 20 photographers’ frames from Sept. 11, 2001, when hijackers crashed commercial planes into New York’s World Trade Center, the Pentagon and a Pennsylvania field.

The perplexing Battle of Los Angeles in 1942 generated swaths of UFO conspiracies

On Feb. 24-25, 1942, weeks after the Pearl Harbor attack, a US military radar warned of enemy aircraft. A citywide blackout went into effect, powerful searchlights were lit up, and US forces fired artillery at what they believed to be the enemy. However, no confirmed enemy planes were ever identified. Eyewitnesses reported seeing large objects flying overhead, and much of the public speculated about UFOs and extraterrestrial attacks.

View artifacts at the Smithsonian that tell the story of 9/11.

Vladimir Putin was the first world leader to call Bush after 9/11, and visited the US two months later.

The toxic dust from 9/11 sites still claims lives decades later

In the years after 9/11, nearly 17,000 first responders enrolled in health programs have reported cancers and respiratory diseases linked to Ground Zero exposure. More have died from related illnesses than were killed on the day itself.

See intact objects found in the wreckage of Flight 93, which crashed in Pennsylvania after its 40 passengers and crew stormed the cockpit, stopping the hijackers from reaching their likely target, the US Capitol Building.

Americans showed an unprecedented surge of patriotism after 9/11

In the weeks following 9/11, 79% of US adults reported displaying the American flag, and a year later, 62% said they "often felt patriotic" due to the attacks.

Conspiracy theories come from distrust in government, media, and institutions

Some believe JFK's assassination was orchestrated by larger networks rather than a lone shooter. Skeptics wondered how one unknown man could kill the most powerful person in America, and believed the CIA, FBI, or Soviet government played a role in the murder.

After the 9/11 terrorist attacks in New York City’s Financial District in 2001, many banks decided to relocate

Much has been said about why today’s top banks are typically no longer headquartered on Wall Street itself. The terrorist attacks in New York City’s Financial District on Sept. 11, 2001, are one reason many banks decided to relocate.

The 9/11 plane crashes, which resulted in the collapse of the Twin Towers, created toxic dust that included materials including asbestos, silica, metals, concrete, and glass.

President Bush threw the first pitch at the World Series in New York City less than two months after 9/11.

There is a secretive bomb-proof bunker located under the White House

Built in 1942 during World War II, the Presidential Emergency Operations Center lies beneath the East Wing. Designed to protect the president during air raids—and later nuclear threats—it remains a top-secret command site used during crises like 9/11.

The attacks prompted a quick jump in American public support for war

In a Gallup poll taken days after the attack, an extraordinary 97% of Americans approved Congress declaring war on Japan—reflecting overwhelming national unity in the wake of the strike.

What 9/11 did to one family: the heartbreaking story of Bobby McIlvaine

Grief, conspiracy theories, and a family's search for meaning in the two decades since the attacks. On Sept. 11, 2001, Bobby McIlvaine was killed, along with nearly 3,000 other Americans. In the years since, his parents and brother have searched for...

NATO has only invoked its mutual defense clause once, in the days after the 9/11 attacks.