16 Years! It has been 16 years since one of the most devastating days in US history - a day which sparked more than a decade of relentless international conflict. Thousands of 9/11 victims' relatives, survivors, rescuers and others are gathering at the World Trade Centre today to remember what remains the deadliest attack on American soil. After 16 years, the quiet rhythms of commemoration have become well known customs - a recitation of all the names of the dead, moments of silence, tolling bells, and two powerful light beams that shine through the night. But each ceremony has personal touches, too.

Todd talks to Ari Fleisher, former White House Press Secretary for President George W. Bush who was by the side of the President that day.