United States President Barack Obama has paid tribute to the people of New Orleans, five years to the day after Hurricane Katrina destroyed large parts of the city.
His administration would stand by them and continue rebuilding "until the job is done", Mr Obama said.
Some 1836 people died on 29 August 2005 when Katrina hit the Gulf coast with winds of up to 201km/h, making it a Category 3 storm on the Saffir-Simpson scale. It had only just weakened from Category 5.
Entire communities on the Gulf Coast were obliterated, and than a million people were displaced and scattered throughout the United States - some of whom have still not returned, the BBC reports.
Ceremonies in New Orleans to mark the anniversary on Sunday include the tolling of the bells at St Louis Cathedral.
Mr Obama made his speech at Xavier University - which, like much of New Orleans, was flooded when the levees protecting the city were breached by flood tides. He described the city as a symbol of resilience and community.
A fortified levee system would be finished next year, Mr Obama pledged.
"We should not be playing Russian roulette every hurricane season," he said.
However, he acknowledged that much remained to be done.
New Orleans Mayor Mitch Landrieu says the city is using the anniversary to show the world it is recovering.
According to US census figures, the population of New Orleans had recovered to 90% of its pre-storm level by July 2009.
In the past few months, the same region hit by Hurricane Katrina has had to cope with the environmental damage caused by the oil spill in the Gulf of Mexico.