Survivors and first responders gathered at Sunrise hospital, which treated more than 200 victims of the shooting

Zack Mesker, a 22-year-old San Diego resident, visited Sunrise hospital in Las Vegas on Monday to thank the people who saved his life last year, on 1 October 2017, when a bullet entered his hip at the Route 91 Harvest festival.

Monday marked the first anniversary of the Route 91 shooting, the deadliest such event in modern US history. Fifty-eight people were killed and 869 concertgoers injured that night by a gunman on the 32nd floor of the Mandalay Bay resort.

“I spent 21 days here,” Mesker said outside Sunrise’s emergency department. “They did what they could to get me up and moving. Some of the finest people work here.” Tracy Szymanski, the guest services director, stood by him and his girlfriend. She also happened to be at the event and escaped the shooting, and in the days and weeks afterward became close with patients.

“They’ve helped me heal probably more than I’ve helped them,” Szymanski said, holding back tears.

Monday was a sober day in Las Vegas. Mourning began at dawn at a public amphitheater where victims’ families, survivors, first responders and community leaders gathered at sunrise to pray, sing, honor the tragedy’s heroes and share stories of grief.

“Scars of October 1 will forever be with us,” the Nevada governor, Brian Sandoval, said. “But today, and every day, we continue to make the choice to triumph over evil.”

Since the tragedy occurred, the community has used the “Vegas Strong” slogan to commemorate the countless episodes of bravery, compassion and resilience that came in the immediate wake of the attack, when blood banks had to turn away donors, provisions piled up outside hospitals and emergency shelters, and stories of heroism emerged. On Monday, the term “Vegas Stronger” was used to recognize the growth that has occurred over the past 12 months, and the resilience with which it enters a second year of healing.

“I’d be lying to you if I said I didn’t think of it often, if not daily,” said Paige Laughlin, a Sunrise operations vice-president who identified victims last year. “Walking through the departments, it’s easy to picture what that night was. It’s who we are now.”

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At 10.05pm, Sunrise staff planned to gather in the hospital’s ambulance bay for a 58-second moment of silence to correspond with the exact minute the first bullet was fired.

As the city’s largest trauma center and the one nearest the strip, Sunrise received 124 gunshot wound victims and more than 200 patients in the first hours after the shooting. Emergency department staff described the scene as a “sea of blood”, and some of them had to deliver hard news to families in waiting rooms outside a warzone-like trauma ward.

On Monday, its halls were occupied by chaplains and therapy dogs. “No one goes through it the same way,” Ellysia Banks, a volunteer chaplain, said of the anniversary. Leading a golden retriever named PJ to a nurses’ station, she added: “Grief isn’t linear. It’s a tangled ball of emotions. On a day like today, some people don’t want to talk about it, and there are those who do. We’re here just to make a space for them to be who they are.”

Several survivors returned to the hospital for the anniversary, explaining a need to develop new memories of the space to replace images seared in their minds from last year. One man said it looked very different. The floors looked different. The walls looked different.

“We look at meeting the survivors, who had that resilience and who persevered through their injuries, and their families, as a celebration,” said the hospital’s CEO, Todd Sklamberg. “The emotion in that room – words cannot begin to capture it. The hugs, the tears of joy – it was a day that none of us will forget.”