9/11 anniversary: Rare images show the aftermath of World Trade Centre attack that killed 2,997
The US is marking the 16th anniversary of the 9/11 attacks which killed 2,997 people and injured more than 6,000.
The suicide missions saw hijacked passenger planes flown into the Pentagon and the Twin Towers of New York's World Trade Centre.
Another hijacked civilian airliner crashed in a field in Pennsylvania.
The worst domestic attack the US had ever experienced, it directly led to then-President George Bush launching the "War on Terror", which continues to have ramifications today.
The Independent is now publishing archive images showing the immediate aftermath of the attacks.
President Bush was visiting a school in Florida when American Airlines Flight 11 crashed into the World Trade Centre's North Tower.
The day's planned activities were quickly abandoned as the President's team scrambled to deal with the fallout.
As another plane hit the second tower, it became clear the collisions were not accidental.
In Washington, Vice President Dick Cheney coordinated the response in George Bush's absence.
On the ground in New York, there was panic as the towers collapsed, flooding the surrounding neighbourhoods with dust.
The rescue effort claimed the lives of 412 emergency responders, including 343 firefighters.
To mark the 16th anniversary, President Donald Trump is scheduled to observe a moment of silence at around the time the first aeroplane hit the tower.
He also planned to participate in a 9/11 observance at the Pentagon.
Also at the Pentagon, Defence Secretary Jim Mattis and General Joseph Dunford, chairman of the Joint Chiefs of Staff, are hosting a private observance for victims' relatives on Monday morning.
Vice President Mike Pence and Secretary of the Interior Ryan Zinke are scheduled to deliver remarks at the Flight 93 National Memorial near Shanksville, Pennysylvania.
Meanwhile, rebuilding continues at Ground Zero. The third of four planned office towers is set to open next year; so is a Greek Orthodox church, next to the trade centre site, that was crushed by the South Tower's collapse. Work toward a $250m (£189m) performing arts centre continues after a design was unveiled last autumn.
Most recently, plans were announced this spring to transform a grassy clearing on the memorial plaza into a walkway and area dedicated to 9/11 rescue and recovery workers, including those who died of illnesses years after being exposed to smoke, dust and ash at Ground Zero.