Overview
- The coordinated Al Qaeda attacks on September 11, 2001 used four hijacked planes to hit the World Trade Center and the Pentagon and crash in Pennsylvania, killing nearly 3,000 people.
- The U.S. responded with Operation Enduring Freedom in October 2001 to oust the Taliban and pursue Al Qaeda and later launched the 2003 Iraq invasion based on claims that were never substantiated and judged unlawful by the UN.
- Guantánamo Bay remains open more than a decade after President Obama's 2009 closure order, with about 800 men having passed through the facility and continuing legal debate over indefinite detention and military commissions.
- The May 2011 raid that killed Osama bin Laden in Pakistan was a major operational success but did not end transnational jihadism and raised questions about the legal use of lethal force without trial.
- Everyday security measures born after 9/11 — stricter airport controls, expanded surveillance and deeper international intelligence sharing — persist, while the wars that followed have left high human and economic costs and helped create conditions for groups like ISIS and the Taliban's return to power.