US marks fifth anniversary of Hurricane Katrina
The US is marking the fifth anniversary of Hurricane Katrina hitting the Gulf coast, killing more than 1,800 people.
President Barack Obama told residents of New Orleans the city had become a symbol of resilience and community.
"It is inspiring to spend time with people who've demonstrated what it means to persevere in the face of tragedy," he said.
The storm displaced hundreds of thousands of people, some of whom have still not returned.
In his speech at the city's Xavier University, Mr Obama praised the efforts already made to rebuild the city, and promised to stand alongside the people of New Orleans "until the job is done".
Sombre ceremonies marking the anniversary will include the tolling of bells at St Louis Cathedral.
A march and "healing ceremony" have also been scheduled in a district of the city where many houses still stand vacant.
The houses still have a circle painted on them in 2005 to indicate that they had been searched, and whether bodies were in them, the Associated Press reports.
"I'm tired of the anniversaries," 77-year-old Barbara Washington told AP, explaining that she had been living in the suburbs since Katrina struck.
"I miss my home every day. I feel lost. But I also know we are getting back. We're survivors."
During a symbolic burying of victims of Katrina in Chalmette, Louisiana, residents were invited to write "farewell Katrina" messages and place them in a coffin, which was then buried.
"You made us stronger and made us realise what was important in life. One day we will feel better," read one note.
Gregory Aymond, Archbishop of New Orleans, led the ceremony, telling the congregation: "Where was God five years ago on this day? Here, weeping with us, and trying to console us in the midst of a natural tragedy."
Hurricane Katrina slammed ashore near New Orleans with winds of up to 125mph (201 km/h) - making it a Category 3 storm on the Saffir-Simpson scale. It had only just weakened from Category 5 and brought ashore a massive storm surge.
Entire communities on the Gulf Coast were obliterated, and than a million people were displaced and scattered around the US.
Many were housed in Federal Emergency Management Agency caravans.
Hundreds of thousands of people fled New Orleans and with much of its housing stock destroyed, the city's population a year after the storm was only half its pre-Katrina level of 1.3 million.
According to US census figures, by July 2009, its population had recovered to 90% of its pre-storm level.