They’re images permanently etched into the minds of billions.
Smoke smouldered from tonnes of wreckage where the World Trade Center once stood while rescue workers waded through the rubble in the days following the September 11, 2001, attacks.
While the aftermath was covered extensively across the media, a new, haunting collection of previously unseen photographs show the devastation at Ground Zero.
A total of 147 powerful images have been released 25 years on from the attacks that left 3,000 dead.
They were all captured by photographer Ringo Chiu in the days following the attacks on New York’s Twin Towers.
His powerful pictures document the extraordinary scenes in Lower Manhattan as first responders and rescue workers worked amid the ruins.
Images show firefighters and emergency crews surrounded by twisted steel, rubble and dust as the rescue and recovery operation continued at Ground Zero.
But away from the destruction, Chiu also captured the intensely personal impact of the tragedy on the streets of New York.
Poignant photographs show candles and makeshift memorials left for those who had died, while posters bearing the faces and names of missing people appeared across the city as relatives and friends desperately sought news of their loved ones.
Other images capture first responders at the scene and the haunting landscape left behind by the collapse of the towers.
Taken over several days in the immediate aftermath of the attacks, the photographs provide a striking eyewitness record of a city experiencing shock, grief and extraordinary uncertainty.
Now, 25 years on, the collection offers a powerful reminder of both the enormous scale of the destruction and the individual lives at the heart of one of the defining events of modern history.
On September 11, 2001, nearly 3,000 people were killed in the coordinated terrorist attacks on the United States.