At the time of the 2001 September 11 attacks in the United States , the corporation held offices on eight floors , 93 to 100 , of the North Tower of the World Trade Center . When American Airlines Flight 11 crashed into the building , its offices spanned the entire impact zone , floors 93 to 99 . Everybody present in the company 's offices on the day of the attack died as all stairwells at impact zone were destroyed or blocked by the crash ; the firm lost 295 employees and 66 contractors
September 11 attacks
September 11 attacks
Marsh & McLennan Companies