_{From the Case File The Day the World Changed}

• _{By all account, the investigation into the September 11, 2001, hijackings were a massive undertaking. Where did the investigation begin? What were the first questions that needed to be answered?}
• _{From the information available and provided here, what were the most significant successes and failures of the authorities in preventing and investigating the September 11 hijackings and related events?}
• _{What do you suppose were the biggest lessons learned by the authorities as a result of the investigations associated with the hijackings of September 11th?}