President Barack Obama has led a moment of silence to remember those who died during the 9/11 terrorist attacks.
Secretary General of Nato, Anders Fogh Ramussen, has tweeted a photograph of the flags at half-mast at NATO headquarters in Brussels to mark the 9/11 anniversary.
In a second tweet, he added: "Deepest sympathy to people of all our countries who suffered from terrorism. NATO's commitment to fighting terrorism remains unwavering."
The US Ambassador to the UK, Matthew Barzun, has tweeted a photograph of a floral tribute sent to the American Embassy in London from David Cameron to mark the 12th anniversary of the 9/11 attacks.
Princes William and Harry cracked jokes with each other as they made multi-billion pound deals for charity on a City trading floor.Read the full story ›
Labour leader Ed Miliband has tweeted that today is a day to remember the victims of 9/11, including the 67 Brits who died in the terror attacks 12 years ago:
A day to remember the victims of 9/11 – including the 67 British people – who lost their lives in New York 12 years ago.
Americans are remembering the thousands of lives lost in the terror attacks of September 11, 2001. This year is the 12th anniversary of the attacks and the tenth year the 'Tribute in Light' has shone above Lower Manhattan to commemorate the twin towers of the World Trade Center.
In Illinois 3,000 flags have been placed in memory of the lives lost in the attack.
A man widowed in the September 11 attacks has returned to the top of the World Trade Center to honour the memory of the wife he lost there.Read the full story ›
The Duke of Cambridge and his younger brother will mark the 12th anniversary of the September 11 attacks on the World Trade Centre and Pentagon by joining traders in London's Docklands to make big deals over the phone.
American global financial services company, BGC Partners, lost 658 employees on 9/11 and has hosted an annual fundraising event in their memory since 2005.
Overall, they have raised £56 million for charity.
Organisers are hoping this year will be no exception - all money generated will be donated to good causes, including SkillForce, of which William is patron, and WellChild, of which Harry is patron.
Financiers BGC Global will be banking on some unlikely new talent to raise funds.
Princes William and Harry are to become stockbrokers for the day at a 9/11 memorial, where they will hit the trading floor to raise money as part of the annual BGC Global Charity Day.
The aircraft part believed to be from one of the hijacked planes that crashed into the World Trade Centre on 9/11 came from a wing, not landing gear.
Police said today that the 5ft part is a trailing edge flap support structure. It is located closer to the body of the plane and helps secure wing flaps that move in and out and aid in regulating plane speed.
Investigators initially thought it was part of the landing gear because both pieces have similar-looking hydraulics.
Workers discovered the part last Wednesday on the ground in a tight space between a luxury loft rental building and a mosque near the World Trade Centre site.