'Heartbreaking' 9/11 footage shows tragedy from rare angle viewers claim they've 'never seen' before

A quarter of a century on, a piece of 9/11 footage filmed from a helicopter has racked up hundreds of thousands of views online after being rediscovered by users who say they've never seen the attacks from this angle.

The clip, shared on X, shows the aftermath of the first plane striking the North Tower of the World Trade Center, filmed from a helicopter hovering nearby.

Moments later, the same footage captures the second aircraft slamming into the South Tower, live and largely unannounced, while a newscaster can be heard on the audio still processing the first impact.

"This is the first time I see this video clip and I thought I saw them all in the last 25 years since 9/11," the user who posted the clip wrote.

The footage arrives just weeks before the 25th anniversary of the terrorist attacks, which killed 2,977 people on September 11, 2001, after four passenger planes were hijacked by al-Qaeda.

Two of those planes were flown into the Twin Towers in New York City, a third hit the Pentagon in Virginia, and a fourth crashed into a field in Pennsylvania after passengers attempted to fight back against the hijackers, in what is widely regarded as the deadliest terrorist attack in modern history.

Why did the newscaster miss the second plane hitting the South Tower?

Part of what has struck viewers about the footage is the audible confusion in the broadcast itself. As the second plane hits, the newscaster can be heard questioning whether something has happened to the South Tower, seemingly unaware in real time that a second aircraft had struck. Commenters below the clip pieced together why: on the original 2001 broadcast, a caller phoned in to alert the newsroom before the visual sank in.

One person recalled the exchange in detail, writing: "I watched this that morning. I didn't see the second plane either. Somebody called in and told them a second plane hit the tower. The newscaster said, 'you're there?' The woman said 'no, I'm home watching on TV! Replay it! Look at the screen to the right!' They did and we saw."

Another user who watched the towers fall in real time described the moment their brain refused to process what it was seeing, writing that they initially mistook the second aircraft for a small plane before it struck the South Tower, adding: "Typing this, I'm back in that moment. Horror. Fear. Abject terror-and rage."

Footage from the attacks continues to circulate online in part because so many people in New York happened to be filming on early digital devices that day, capturing the disaster from angles never broadcast on television at the time. New clips are still being unearthed and shared a quarter of a century later, often triggering fresh waves of shock from people who lived through the day and are seeing a previously unseen perspective for the first time.

Others recalled watching the coverage unfold from thousands of miles away.

One user said they were on business in Sydney and initially assumed the footage was a film before the second plane hit and reality set in, writing: 'I will never forget that day. Never forgive, never forget.'

An estimated 6,000 to 25,000 people were injured in the attacks, alongside the nearly 3,000 killed, with the anniversary later this month expected to prompt further footage and testimony to resurface online.