Over the next four weeks, we are exploring Newstalk’s 20 most influential moments of the past two decades, as chosen by our listeners.

One of those moments took place on September 11th 2001; one of the worst terror attacks in modern history and a day that is etched in people’s memories forever. 

It was a turning point in terrorism, instilling a new level of fear in people across the globe.

So, are we still facing the same threats and what lies ahead? 

Colin P. Clark is the author of ‘After the Caliphate: The Islamic State & the Future Terrorist Diaspora’ and Chris Phillips is the former Head of the UK National Counter Terrorism Security Office.

They joined Mark on Tuesday's edition of The Hard Shoulder to give their analysis.

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