Memorial services will be held today to mark the 25th anniversary of the 9/11 attacks in the United States
On 11 September 2001, 2,977 people were killed when hijackers crashed three planes into the World Trade Center in New York City and the Pentagon in Virginia
A fourth hijacked plane crashed in a field in Pennsylvania after passengers fought back
A London event to honour the victims is under way at Queen Elizabeth Olympic Park - UK PM Burnham has paid tribute to 9/11 victims, including the Britons killed that day
We've been hearing from people who were in New York on 9/11. Janice Brooks tells us she was being evacuated from her office, when the second plane plane hit with an "almighty thud"
The 9/11 attacks, along with the response, came to define a generation of foreign, security and intelligence policy for the first two decades of this century, says the BBC's Frank Gardner
