On September 11, 2026, the United States marks 25 years since the deadliest terrorist attack ever carried out on American soil, an event that continues to shape the nation far beyond the immediate tragedy that unfolded in New York, Washington D.C., and rural Pennsylvania.
The coordinated al-Qaeda attacks of September 11, 2001 killed 2,977 people on the day of the tragedy. More than 2,700 of those fatalities occurred at the World Trade Center site in Lower Manhattan, where the Twin Towers collapsed after being struck by two hijacked commercial airliners. Among those killed in the World Trade Center collapse were 343 New York City firefighters, 23 local police officers, and 37 Port Authority police officers who rushed into the burning buildings to evacuate trapped civilians, according to data compiled by CNN.
But a quarter century later, the human cost of the attacks is still climbing. Long-term exposure to toxic dust from the collapsed World Trade Center has led to a widespread public health crisis among first responders and survivors who lived, worked, or provided recovery support in the area after the attack. More than 57,000 people enrolled in the federally run World Trade Center Health Program have already been diagnosed with 9/11-related cancers, and as of March 2024, close to 7,000 program enrollees have died from exposure-linked illnesses. Tens of thousands more remain under ongoing medical monitoring and require long-term treatment for chronic respiratory and cardiovascular conditions linked to toxic dust exposure.
This 25th anniversary has reignited public and political scrutiny over decades-old claims of official deception surrounding air safety at Ground Zero in the weeks and months after the attack. In a major shift following years of legal battles and public pressure, New York City recently released more than 170,000 pages of previously classified internal documents related to post-attack air quality testing and government communications. The release has opened new avenues for researchers and victims’ families to assess whether officials downplayed known health risks to speed up the reopening of Lower Manhattan.
Commemorative ceremonies were held across the country to honor the lives lost on 9/11. At the 9/11 Memorial in New York City, built on the site of the collapsed Twin Towers, family members gathered to read the full list of victims killed in the attacks, continuing a tradition that began in the first years after the tragedy. U.S. President Donald Trump led the federal government’s commemoration at the Pentagon, the site of the third hijacked plane crash, where 184 people were killed on September 11, 2001.
Twenty-five years on, the 9/11 attacks remain a defining turning point in modern American history, shaping everything from foreign policy and national security to public health policy. As the nation honors those killed, the ongoing public health crisis and new disclosures of previously hidden records ensure the legacy of that tragic day continues to evolve, even as the country works toward collective healing.