A quarter of a century after hijacked planes struck the World Trade Center, the Pentagon, and a field near Shanksville, Pennsylvania — killing nearly 3,000 people on a single September morning — the world is still grappling with the consequences. Commemorations this week have prompted reflection not only on the grief of survivors and victims' families, but on the sweeping geopolitical, social, and human toll of the era the attacks set in motion.

For many families, the pain remains searingly immediate. In New York, the remains of more than 1,000 of the 2,753 victims who died at the World Trade Center have still never been identified. Forensic scientists at New York City's Office of Chief Medical Examiner continue to work through one of the most complex identification efforts in history, using advances in DNA technology — including a technique called forensic investigative genetic genealogy — to bring answers to families who have waited decades. Last month, authorities announced the identification of the 1,654th victim, and officials say the work will continue as long as families are still searching. For some, like Juliette Scauso, whose firefighter father Dennis has never been recovered, the prospect of a call from the medical examiner's office is itself a source of dread as much as hope. "An identification wouldn't change the reality of his death," she said. "Especially 25 years later, it's going to open up the wounds again."

The anniversary has also been marked by questions about who belongs at the commemorations. Calls for New York's first Muslim mayor, Zohran Mamdani, to stay away from the ceremony — including from former mayor Rudy Giuliani — have prompted a broader reckoning with how the attacks reshaped attitudes toward Muslim and Arab communities in the United States. The brother of Salman Hamdani, a Muslim American police cadet killed in the North Tower, spoke of Islam being "hijacked" by the narrative that followed. In the 25 years since the attacks, American Muslims have faced surveillance, discrimination, and political targeting, even as their communities have grown in size and influence. Scholars note that Islamophobia in the US tends to intensify around election cycles, not just in response to security events — a pattern they say is visible again in the current political climate.

Beyond American shores, the attacks triggered a cascade of military interventions whose human cost dwarfs the tragedy of that single day. Research by Brown University's Costs of War project estimates that US-led wars since 2001 have killed between 4.5 and 4.7 million people — including around 940,000 direct deaths and millions more lost to war-induced disease, displacement, and malnutrition. Afghanistan, invaded in October 2001, saw approximately 176,000 direct war deaths over nearly two decades of conflict. Iraq, invaded in 2003 on disputed grounds, suffered around 315,000. The Taliban, ousted within weeks of the initial invasion, returned to power in Kabul in 2021.

Analysts argue that the post-9/11 era fundamentally eroded the US-led international rules-based order, creating a geopolitical vacuum that emboldened authoritarian powers and strained multilateral institutions. The simultaneous wars in Afghanistan and Iraq stretched American military and financial resources, while the 2008 financial crisis compounded the damage to US global standing. The United Nations Security Council, paralysed by the veto powers of its permanent members, has been reduced to an observer role in successive crises. For smaller nations — including those that joined US-led coalitions out of solidarity — the era has forced difficult reassessments of sovereignty, alliance, and strategic independence. The central lesson many draw from the past 25 years is both simple and sobering: military power alone cannot resolve the deep political grievances that breed mass violence, and the costs of trying can echo across generations.