Much of the relief effort involved getting water and food to victims
The street outside New Orleans convention centre is littered with the debris of thousands of people now evacuated from the city.
Chairs, overflowing bin liners, empty plastic water bottles, barbeque grills, sandbags and stained mattresses line the street for hundreds of metres.
They tell a grim story of how people were living until very recently in a city where lawlessness is rife.
Inside there is the stench of rotting food and urine, but also signs of the way the disaster brought some together.
Chairs are clustered in circles, where groups of friends and family helped each other through the ordeal.
At the other main centre where people gathered in the vast bowl of the Superdome, water still surrounds the building, almost covering cars.
But at the rear, military helicopters land on a raised area, drawing groups of people hoping for evacuation towards them.
Without food, water or power for many days, some are only now emerging from their homes, even using the deserted motorway flyovers to move about the city.
Nasseem and Karen Hassan push a shopping trolley loaded with their remaining possessions. They are hoping the National Guard will help them reach family in Atlanta, but Naseem told BBC News that many were determined to stay.
"Eventually they will have to go around door to door if they want to clear the city. People have no power or food, but their home is all they've got."
Much of the rest of the city is eerily silent - rubble, rubbish, broken windows and damaged buildings tell of what went before.
National Guard troops with rifles man checkpoints, overhead military helicopters hover incessantly. On the horizon a cluster fly around a plume of dark smoke.
Convoys of emergency vehicles stream past on the flyover, suggesting much in the city remains chaotic.