It is 10 years since the World Trade Center was reduced to dust and ash. Rudy Giuliani was the mayor of New York City on its darkest day. His response back then earned him the title "America's mayor" and he won worldwide admiration, but how much have he and his country been changed by 9/11?
He spoke to Stephen Sackur about why he believes that prior to 9/11 America's national security response was insufficient.
Watch the full interview on BBC World News on Thursday 8th September at 08:30 GMT, 15:30 and 20:30 GMT and on the BBC News Channel on Friday 9th September at 00:30 and 04:30 BST.
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