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By Ghaith Abdul-Ahad and Teresa Smith
Ghaith Abdul-Ahad is an award-winning photographer and journalist from Iraq.
He began documenting life on the streets of Baghdad in 2001 and, when the Iraq war started two years later, he reported for The Guardian newspaper on those parts of the Iraqi capital that were simply too dangerous for outsiders to cover. But growing violence forced him to leave the city.
In Baghdad, City of Walls Ghaith returns to the streets of a Baghdad now divided by security walls separating the city's Sunni and Shia residents.
Thousands of homeless roam the streets, children grow up hating Americans, the dead are buried in improvised cemeteries and there is electricity for only three hours a day.
Ghaith's ability to move around the city despite the dangers, gives us a unique insight into this Baghdad and to a story so far untold.
Baghdad, City of Walls airs from Sunday, April 5, 2009 at the following times GMT: Sunday: 1430; Monday: 0600, 1900; Tuesday: 0300.