Following the first firefighters on the scene and their race against time to rescue trapped civilians.

Stories of escape from the South Tower and the paramedics on the ground facing an onslaught of badly injured people.

A day of terror and the struggle to survive continues as the Pentagon is hit, Flight 93 is hijacked and the South Tower collapses.

Survivors search for loved ones after becoming separated when they are enveloped by a toxic dust cloud.

It is a race against time to find and rescue a group of firefighters who were inside the North Tower when it collapsed.

At Ground Zero, two ex-marines and an ex-paramedic join forces to search for survivors and pull off one of the most miraculous rescues of the day.