Standing amid the large crowd taking over Hope Street during Saturday night’s Grand Illumination celebration were Danielle Fox and her 3-year-old son, Declan. He was dancing blissfully to the music, while she was counting down the seconds until her son could watch the world turn from dark to light.

It was a magical moment for the family, celebrating their first Christmas living in Bristol.

“We did something like this in Taunton, but it wasn’t the same,” Ms. Fox said.

The Fox’s were one of the many families swept up in the festivities on Dec. 1, enjoying an evening filled with music and entertainment from the Colt Andrews and Rockwell Guiteras choruses, Mt. Hope Vocal Ensemble, Will Sousa Grapentine, Lexi Lanni and the Extensions School of Dance. Hits such as “O Holy Night” and “Winter Wonderland” were sung, reindeer costumes and Santa dresses were worn. The event, a Bristol staple since 1987, has become a fixture for many during the holiday season.

“It’s kind of become a family tradition,” said Caitlin Swift, a resident of Mattapoisett, Mass. Ms. Swift has been attending the Grand Illumination for the last 12 years alongside her aunt and cousin, Susan and Madeleine Green, the latter of whom had previously danced with the Extensions School of Dance.

While the event may be rooted in tradition for many people, it didn’t stop this year’s co-chairs, Nat and Patty Squatrito, from throwing a curveball into the crowd. The pair kept the arrival of Santa a mysterious secret, leaving everyone guessing until the moment the spotlight appeared on the balcony of the Belvedere building and Miss Lanni led the town in belting out “Santa Claus Is Coming to Town.”

From there, Mr. Claus made his way through the crowd like a celebrity as he headed to where Miss and Little Miss Fourth of July stood waiting at the Burnside Building, ready to light the town.

In an instant, Bristol transformed; suddenly, everyone was standing under a canopy of lights twinkling against the night sky while before them, the colorful, sparkling tree stood. Though the night ended shortly after, in that moment, the most wonderful time of the year in Bristol officially had begun.