Chilling video of New York's bravest was taken on September 11th in the North Tower of the World Trade Center by filmmakers who happened to be shooting a documentary about firefighters when the attacks occured.
Planes taken over by terrorists had hit both towers and there was controlled chaos as firefighters figured out a rescue plan. But then, the South Tower collapsed.
It's the only footage known to exist from inside the World Trade Center from that terrible day. The footage airs on CBS this Sunday in 9/11: Ten Years Later.
Producers James Hanlon and Jules Naudet tracked down the firefighters who were filmed on 9/11 to see where they are now. INSIDE EDITION spoke to Hanlon and Naudet.
"The resilience of these guys, no matter what was going on, they had a job to do and they went to do it," said Hanlon.
"At the moment where we saw the worse of humanity, I saw the best," said Naudet.
It's just one of many shows being rolled out to commemorate the 10th anniversary.
Showtime is showing Rebirth with a striking time-lapse of Ground Zero over 10 years.
And MSNBC takes an emotional look back with anchors and reporters who covered 9/11. There's one correspondent who has been credited with being the first to use the term "Ground Zero" in connection with the terror attacks. It was NBC's Rehema Ellis.
"The closer we get to Ground Zero the harder it is to breathe, to see," said Ellis while covering the attacks.
Her report aired just hours after the attacks. 10 years later, she says she never intended for it to become a famous catch phrase.
"I felt then that we were at that moment, we were at that place. This is where it all happened. This is the ground zero of this event," said Ellis.
Images of our nation's darkest day—remembered 10 years later.