Twenty years ago, two passenger planes slammed into both towers of the World Trade Center in New York. It was the worst terrorist attack in US history, watched live around the world. In this special show, we try to understand how the consequences are still being felt today. We talk to first responders who now suffer from devastating health issues. We also see how security measures were stepped up in the wake of the attacks and how education has adapted to a new generation that wasn't born during 9/11.
