This weekend, serial killers, rotting zombies and clowns will take to the streets. In its 23rd year, Nightfall returns to Old Tucson today with new attractions and scarier shows.

For the better part of the year, Old Tucson is a Western-themed town whose streets are trodden by cowboy boots and horses drawing carriages. But for one month out of the year, the park is transformed into a Halloween-themed attraction for the Tucson community.

In its early days, the theme of Nightfall followed an evil doctor who performed experiments on the patients in a local asylum. Today, the park makes an effort to introduce a variety of Halloween scares, from post-apocalyptic dead zones to clowns with beady black eyes.

Rob Jensen, the manager of entertainment for Old Tucson, said that Nightfall is trying to raise the bar this year in terms of the entertainment it has to offer.

“Each year is always about topping previous years,” Jensen said. For example, he added, Nightfall has moved its largest stunt and pyro show into the rodeo arena, allotting more space for stuntmen to perform. “You can spend six hours out here on a Nightfall night and never get bored.”

Audience members can expect dangerous stunts this year, such as a motorcyclist jumping through a 50-foot ball of fire, according to Pete Mangelsdorf, the chief executive officer and general manager of Old Tucson.

Nightfall will also introduce a magic and illusion show this year called “Magic of the Macabre,” performed by John Shryock and Mari Lynn. It is also bringing back the train ride, run by gargoyles, to appeal to children.

Mangelsdorf said the park has set itself apart from other haunted attractions.

“From the moment you walk into Old Tucson, it’s an experience,” Mangelsdorf said. “We have an entire town, not just a single haunted house.”

Old Tucson has been built on a foundation of fame and tradition, hosting more than 300 movies and shows since 1939, and Nightfall has been running for over 20 years.

At this time each year, the dusty roads and rustic buildings are transformed into the largest haunted town in Southern Arizona, according to Jensen.

“We pride ourselves in being the largest and longest-running Halloween attraction in Southern Arizona,” Jensen said.

Although Nightfall has earned its reputation in Tucson as a frightening park, its organizers are also looking to include attractions for children. Among other walkthroughs, the “Creepy Crawly Cave” was created for children and people with a low scare tolerance.

“There are some areas of the town that are tamer than others,” Jensen said. Walkthroughs are rated with one, two or three skulls to give attendees a general idea of how scary each attraction is.

A carousel and inflatable attractions have also been introduced to the park.

Andrew Kenworthy, the creative director of Old Tucson, said the organizers get a six-month creative stretch each year to plan how they will reinvent Old Tucson as Nightfall.

“We try to mix things up,” he said, adding that his team goes through an extensive creative process to ensure that the park never uses the same idea more than two years in a row.

This weekend, the park will offer an opening special: Entry is only $15 for all ages. Until Oct. 31, Nightfall will be open Thursdays through Sundays.

On Thursdays, the park will give a $10 discount to college students who show their ID and two Coke product receipts, bringing the price of admission to $15.

“It’s really a party atmosphere; it’s not just a haunted house,” Jensen said. “If we can put a smile on people’s faces, give them a good scare and give them a night out to forget their worries, we’ve done our job.”