Memorials held to remember 16th anniversary of 9/11

On the sixteenth anniversary of 9/11 - terror experts are warning most attackers are now 'homegrown'.

A memorial service will be held at ground zero in New York later to remember the 3,000 people who died on September 11th 2001. Another 6,000 people were injured when hijackers took over four planes and deliberately crashed them.