Shocking video shows plane passengers' chilling reaction to first hearing of the 9/11 terrorist attacks

Gut-wrenching footage filmed on 9/11 caught the moment a plane full of passengers learned about the terror attacks.

Many young people growing up now are familiar with 9/11 as a part of history, but there are millions of people who are able to recall exactly where they were and what they were doing when they learned that multiple planes had been hijacked on September 11, 2001.

One video forever captured that moment in time, showing dozens of people on another plane listening to the crew as they described the events that had unfolded.

See the harrowing footage below:

The clip, which has been credited to Frank Pizzo, has resurfaced on Twitter ahead of the upcoming 23rd anniversary of the attacks.

Speaking over the plane's intercom, the crew member attempted to stay calm as they informed the passengers of the attacks, having learned about them by an outside source.

It would be natural to assume that such horrendous news would elicit screams or cries from the passengers, but the video instead shows an eerie silence fall over the cabin, with only the occasional murmur of shock as the events were relayed.

Passengers reacted to the horrific news. (Frank Pizzo/CTTV)

Some passengers put their faces into their hands in shock, and one woman appeared to break down in tears as she spoke to someone on the phone.

Nearly 3,000 people died in the attacks in which the hijackers took control of four planes.

Two of them were crashed into the World Trade Center and one into the Pentagon. The fourth hijacking, Flight 93, failed after passengers revolted onboard, forcing the terrorists to crash the plane in Somerset County, Pennsylvania instead of its intended target of Washington DC.

In the wake of the attacks, the entirety of US airspace was grounded for civilian flights, meaning around 5,000 aircraft had to be landed in around two hours.

It's nearly been 23 years since the attack. (Fabina Sbina/ Hugh Zareasky/Getty Images)

The attacks were later found to have been carried out by Al-Qaeda; the terrorist organisation founded and led by Osama bin Laden.

Al-Qaeda carried out the 9/11 attacks as part of a strategy to challenge US foreign policy, and in their aftermath the US and its allies began the war in Afghanistan which would ultimately continue until 2021.

The resurfacing of the footage has prompted other people to share their memories of where they were when the attacks took place, with one person responding: "I was a sophomore on [high school] and they sent us home from school.

"I lived a mile from the beach in S. Fl. and drove down A1A to see naval ships and aircraft as far as the eyes could see up and down the coast. Absolutely surreal."