A massive Baghdad bombing a decade ago, termed "the 9/11 of the UN", killed 22 people and drove heightened security measures that ultimately limited interactions with ordinary Iraqis.
On August 19, 2003, a suicide bomber detonated an explosives-rigged truck next to the Canal Hotel, which housed United Nations offices, killing Brazilian UN envoy Sergio Vieira de Mello and 21 others.
At the scene of the attack -- which made headlines around the world as one of the first such bombings in Iraq -- little has changed over 10 years.
One corner of the hotel still looks like it was smashed by a giant hammer, the remains of floors jutting out from the building, rooms strewn with rubble and covered in dust.
Rusted metal reinforcing rods hang from the structure like vines that have long since withered and died, and a blue United Nations helmet still sits near the site of blast.
Marwan Ali was a political officer for the UN mission who escaped the attack because he went across the hall from the section of the building that was destroyed just before the blast.
The explosion threw him to the ground, but did not wound him.
"I was given a new life," Ali, who is now the director of political affairs for the UN in Iraq, told AFP.
Immediately "after the explosion, I went back to where my friend was, and then I found him dead, together with another colleague," said Ali, who worked to help those who survived.
"It is the 9/11 of the UN," Ali said. "It has changed the whole security position."
Before the Canal Hotel bombing and another blast against the UN in September 2003, Ali said he was able to travel around Iraq in an unarmoured vehicle.
But after the attacks, many UN staffers were moved out of the country.
Most are now back in Iraq, but the UN headquarters is located in Baghdad's Green Zone -- a highly secure area housing sensitive Iraqi government buildings and foreign embassies, which is difficult for most Iraqis to access.
The area is surrounded by concrete walls and defended by soldiers armed with weaponry ranging from assault rifles to US Abrams tanks, while the UN facilities inside are protected by more walls and guards.
And staff travelling outside the Green Zone are escorted by guards and ride in armoured vehicles.
The measures, especially the move to the Green Zone, have limited the UN's contact with Iraqi citizens.
"Our interaction with the Iraqis (has) become less," said Ali.
UN staff were able to maintain contact with Iraqi politicians and other figures, but "we more or less lost contact with the population," he said.
"The issue of movement is crucial for us," Ali said, as the UN needs "to interact and to get the real impression and to show visibility."
It is important for the "United Nations to be seen as helping -- we are helping, but we are not seen by (the) public."
While increased security measures pose challenges, the UN is still active in Iraq and has staff around the country.
The mission works on issues ranging from Iraqi-Kuwaiti relations, elections and national reconciliation, to Syrian refugees and Iraqis forced to flee their homes by violence.
Salim Lone, the UN mission spokesman in 2003, is another survivor.
On the day of the blast, he would have been in a meeting in Vieira de Mello's office, but had to work on a statement in his office across the hall.
"That is what saved my life," said Lone, who was wounded in the neck by the explosion. "Except for one person, everyone died who was in that meeting."
"My office was completely ruined," he told AFP. "There was smoke everywhere... you heard screams everywhere."
Lone did not renew his contract with the UN after the blast and returned home to his native Kenya, where he is writing a book.
The attack "made me a very closed person... and for many years, my memory was terrible," though this has improved, Lone said.
The United Nations has been targeted in other countries, but "the first really substantive attack against the UN" was at the Canal Hotel, said Ali.
The effects of that blast are felt to this day by both survivors and the UN as a whole.