Jerome Williams Nola hugs his wife Ashley Williams along the floodwall of the Lower Ninth Ward of New Orleans, during an event to commemorate the 20th anniversary of Hurricane Katrina on Friday. (AP Photo/Alex Brandon)

NEW ORLEANS (AP) — Twenty years after Hurricane Katrina devastated the U.S. Gulf Coast with catastrophic storm surge and flooding, New Orleans marked the storm’s anniversary Friday with solemn memorials, uplifting music and a parade that honored the dead, the displaced and the determined survivors who endured and rebuilt.

Dignitaries and longtime residents gathered under gray skies at the memorial to Katrina’s victims in a New Orleans cemetery where dozens who perished in the storm but were never identified or claimed are interred.

“We do everything to keep the memory of these people alive,” said Orrin Duncan, who worked for the coroner when Katrina hit. He comes to the memorial every year, opening the cemetery gate and making sure the grass is cut.

A Category 3 hurricane when it made landfall in Louisiana on Aug. 29, 2005, Katrina inflicted staggering destruction. The storm killed nearly 1,400 people across five states and racked up an estimated $200 billion in damage, flattening homes on the coast and sending ruinous flooding into low-lying neighborhoods.

Two decades later, it remains the costliest U.S. hurricane on record, according to the National Oceanic and Atmospheric Administration.

The failure of New Orleans’ federal levee system inundated about 80% of the city in floodwaters that took weeks to drain. Thousands of people clung to rooftops to survive or waited for evacuation in the sweltering, under-provisioned Superdome football stadium.

In New Orleans’ Lower Ninth Ward, a predominantly Black community ravaged by flooding when parts of the protective levee collapsed, hundreds watched Friday as an ensemble of white-clad children atop the levee wall sang a song of sorrow and survival.

“We are the children of the ones who did not die,” they sang. “We are the children of the people who could fly. And we are the children of the ones who persevered.”

The population of New Orleans, nearly half a million before Katrina, is now 384,000 after displaced residents scattered across the nation. While New Orleans remains a majority Black city, the exodus disproportionately affected its Black residents. Tens of thousands were unable to return after Katrina. A federal rebuilding program favored the city’s predominantly white and wealthy neighborhoods and failed to reach many in need.

After the storm, the levee system was rebuilt, public schools were privatized, most public housing projects were demolished and a public hospital known for serving the city’s poor was shuttered.

New Orleans resident Gary Wainwright said never misses the cemetery memorial service on Katrina’s anniversary. On Friday he wore a frayed red necktie, covered with the phrase “I love you.” He salvaged it from his battered home in the storm’s aftermath.

“It’s a little bit tattered, like the city,” Wainwright said. “But it’s still beautiful.”