For almost two weeks, crews have sifted through the rubble of the collapsed Champlain Towers South apartment building in Surfside, Florida.
Amid the ruins, they've unearthed 54 bodies, but officials now say there are no signs that any survivors might still be found.
On Wednesday, officials announced they are ending their search and rescue operation and instead shifting to recovery efforts in hopes of finding the bodies of the 86 people who are still unaccounted for.
"At this point, we have truly exhausted every option available to us in the search and rescue mission," Miami-Dade County Mayor Daniella Levine Cava told reporters.
Early in their search, officials said they had detected sounds like banging under the steel and concrete debris — a hopeful sign.
By Tuesday, however, fire officials said they no longer heard any sounds or saw any indications that there were still survivors in the wreck.
Crews have used sonar, cameras, dogs, and heavy machinery in their search, Cava said, working against fire, smoke, and torrential rain.
Rescuers had looked for "livable space," for example, but were "not seeing anything positive that continues in that space," Miami-Dade County Fire Chief Alan Cominsky told reporters Tuesday.
After assessing the wreckage and other factors, officials said Wednesday that the chances of anyone surviving in the rubble are "near zero."
"Today's news is extremely tough for all of our search and rescue professionals," Surfside Mayor Charles Burkett said. "We've all worked passionately day and night for two weeks to save lives."
Cava said that the search will officially become a recovery mission at midnight.
"We have all asked God for a miracle," she said. "So the decision to transition from rescue to recovery is an extremely difficult one."
Nearly half of the building's 136 units were destroyed in the collapse.
Officials believe the viability of finding survivors is slim in part because of the "pancake collapse" of the building, Ray Jadallah, assistant fire chief of the Miami-Dade Fire Rescue Department, said.
Floors and walls of the building stacked onto one another, Jadallah said, leaving little space for people to survive. Crews who had at first looked for sounds and other signs of life had switched to instead look for such "livable spaces" during the search but found few during their efforts.
"Typically an individual has a specific amount of time in regards to lack of food and air, and this collapse, you know, doesn't provide any of that sort," Jadallah said.
One section of four floors that fell onto one another, for example, left only 3 feet of space between them, he said.
Crews had at one point shifted their attention to the east side of the building near a staircase in hopes of finding spaces but were left disappointed.
"It was just unprecedented, the lack of void for survivability," Jadallah said.
Cava said family members of those missing were notified just before the public announcement was made.
"To share news with the families who are still missing their loved ones was devastating," she said.
Crews are expected to remain on the site for weeks. Cominsky said they will continue to work in hopes of finding everyone missing.
"We know what our goal was all along, and we continue going forward in trying to locate everyone's loved ones," he said.
Crews will stop work Wednesday night just before the transition, she said, to mark the hard decision with a moment of silence.
"Please pray with me for those we have lost and those we are mourning," she said.