ORLANDO, Fla. – Church bells will toll throughout the Orlando area as residents reflect on the 49 patrons killed during a massacre at Pulse nightclub in the worst mass shooting in recent U.S. history.

Starting in the early hours Monday, and continuing almost 24 hours later, survivors, victims’ families, city officials and central Florida residents will remember the victims with four services.

Hundreds gathered on Saturday morning at the city’s Wadeview Park to participate in the “CommUNITY Rainbow Run” 4.9K race. Pulse nightclub owner Barbara Poma waved a sign as runners passed by that read: “We will not let hate win,” CBS Orlando affiliate WKMG reports.

Poma said community members are leaning on each other as the first anniversary of the shooting approaches.

“Orlando will always show how united we are,” she told the station.

Monday’s first service is closed to the public, and it’s being held at the nightclub for survivors, local officials and club employees. It will overlap with the exact time that gunman Omar Mateen began firing shots — a little after 2 a.m. on June 12, 2016.

It is followed by another midday service at the nightclub, and an evening gathering in the heart of downtown Orlando. A final, music-filled late-night service is being held at the nightclub.