(New York, N.Y.) - Eighteen years ago, 19 al-Qaeda operatives hijacked U.S. commercial airliners and flew them into the World Trade Center in New York City and the Pentagon in Washington, D.C. A fourth hijacked airplane crashed in a field in rural Pennsylvania. The attacks—the deadliest ever on American soil—killed nearly 3,000 civilians and injured thousands more. Within weeks, the U.S. launched military operations against al-Qaeda’s suspected safe havens in Afghanistan. That December, al-Qaeda’s co-founder Osama bin Laden is believed to have escaped U.S. bombing in Afghanistan’s Tora Bora Mountains and fled to Pakistan.

Bin Laden, who orchestrated the 9/11 attacks, was ultimately killed in a U.S. counterterrorism operation in May 2011. However, al-Qaeda remains every bit the malevolent and determined force it was in 2001. Al-Qaeda’s reach extends well beyond Afghanistan, with branches in the Arabian Peninsula, North Africa, and South Asia—all of which have carried out terror attacks in the recent past.

CEP has documented al-Qaeda and its affiliates’ doctrine; organizational structure; financing, recruitment, and training activities; history; violent activities; government designations; associations; and rhetoric.

• To read the CEP report, Al-Qaeda, please click here.
• To read the CEP report, Al-Qaeda in the Arabian Peninsula (AQAP), please click here.
• To read the CEP report, Al-Qaeda in the Islamic Maghreb (AQIM), please click here.
• To read the CEP report, Al-Qaeda in the Indian Subcontinent (AQIS), please click here.