Al-Qaeda Spent Up to $500,000 Financing the 9/11 Attack Over Two Years

The September 11 attacks, one of the deadliest terrorist strikes in history, were financed by Al-Qaeda over a period of nearly two years. The total cost of planning and executing the attacks is estimated to have been between $400,000 and $500,000. The funds were used to support the hijackers as they prepared and carried out the coordinated assault. The financing operation highlights the logistical and financial infrastructure that Al-Qaeda had built to support large-scale terrorist operations.