9/11: A decade later

The ten-year anniversary of the 9/11 attacks on the World Trade Centre is observed in New York City today as people gather for a ceremony at Ground Zero.

US President Barack Obama and First Lady Michelle Obama, along with former president George W. Bush and his wife Laura Bush, are all in attendance.

The coming together of Obama and Bush, who was president when the 9/11 attacks occurred, sent out a message of unity on the occasion. (AFP Photo)

A view of the 9/11 memorial in New York, September 11, 2011, during the official ceremony marking the 10th anniversary of the terrorist attack. In the September 11, 2001 attacks, Al-Qaeda hijackers crashed passenger planes into the World Trade Centre in New York and the Pentagon in Washington, while a fourth jet crashed in Shanksville, Pennsylvania. (AFP Photo)

(L-R) US President Barack Obama, former US President George W. Bush and US First Lady Michelle Obama and visit the 9/11 memorial. (AFP Photo)

President Barack Obama visit the 9/11 memorial on September 11, 2011. (AFP Photo)

US President Barack Obama and First Lady Michelle Obama pay their respects after laying a wreath during a commemoration ceremony.

The commemoration ceremony at Ground Zero. (AFP Photo)

A woman carries a remembrance of a relative. (AFP Photo)

New York City Police Officer Danny Shea, a military veteran, salutes at the North pool of the 9/11 Memorial during ceremonies. (AFP Photo)

Two presidents and their wives stand at attention as the National Anthem is played. (AP Photo)

Former president George W. Bush speaks at the ceremony. (AFP Photo)

President Obama speaks at the memorial.

Obama opened a sun-splashed day of solemn remembrance on Sunday by honoring the 9/11 dead with a visit to ground zero, bowing his head at the cascading pools of the North Memorial Pond created in the footprint of the demolished north tower of the World Trade Center. (AFP Photo)

A woman carries a poster of a relative before the 10th Anniversary commemoration. (AFP Photo)

Teneal Colbert, 15, right, her brother Fredrick Meeks, 9, left and brother Tyrus Colbert, 14, top left, of Garden City, New York, watch a large monitor broadcasting ceremonies near the World Trade Centre site. (AP Photo)

A woman grieves at the South 9/11 Memorial pool. (AFP Photo)

Another woman mourns. (AFP Photo)

A New York Fire Department firefighter salutes during the singing of the Star Spangled Banner at the entrance of the 9/11 Memorial Plaza. (AFP Photo)

Secret Service snipers patrol the roof of the 9/11 Memorial Museum during tenth anniversary ceremonies at the site of the World Trade Centre. (AFP Photo)

President Obama (L), Michelle Obama, George W. Bush and Laura Bush walk away from the memorial wall on the North Tower reflecting pool of the World Trade Centre. (AFP Photo)

A woman holds up a picture of one of the victims of the 9/11 attacks.

A toddler takes an impression of her aunt's name at the North Pool of the 9/11 Memorial during tenth anniversary ceremonies at the site of the WTC.

A woman and an adolescent stand by the wall by the north pool of the September 11 memorial. (AP Photo)

A woman cries while looking at the names inscribed at the North Pool of the 9/11 Memorial. (AFP Photo)

People stand in the street in lower Manhattan during a ceremony marking the 10th anniversary of the 9/11 attacks outside the World Trade Centre. (AP Photo)

People run their hands over names inscribed on the plaque by the reflecting pool at the 9/11 memorial.

Those gathered commemorate their loved ones who died at the World Trade Centre with signs and posters.

New York police, firefighters and Port Authority police arrive at the Memorial. (AP Photo)

Town residents stand along state Highway 160 waving American flags to commemorate the 10th anniversary of the September 11 attacks in Pahrump, Nevada.

A woman wipes her tears at the memorial.

Small American flags adorn the edge of the south pool of the memorial during tenth anniversary ceremonies.

Crowds have gathered at Ground Zero.

Family members who lost loved ones in the 9/11 attacks visit the North pool. (AFP Photo)

Singer James Taylor performs “Close Your Eyes”.

Coming up: UK prays tribute...

(From Left to Right)The Prince of Wales with his wife The Duchess of Cornwall, Britain's Prime minister David Cameron, Deputy Prime Minister Nick Clegg and London Mayor Boris Johnson at a memorial ceremony for the 9/11 victims in Memorial Garden, London.

The US ambassador Louis Susman, left, with Britain's Prime Minister David Cameron pay tribute to the victims of the US terror attacks, during a ceremony at the 9/11 Memorial Garden in London.

People in London laid out flower tributes to the victims of 9/11 terror attacks in the 9/11 Memorial Garden.

Coming Up: Colosseum in Rome lit up to honour the victims of 9/11...

Colosseum in Rome lit up to honour the victims of 9/11 on the 10th anniversary of the attacks.

Rome light up the Colosseum on Sunday in a show of solidarity.