Trap doors and trinkets: The history behind the Mystery Castle, a whimsical sandcastle come to life in the Arizona desert

At first sight, the hideaway on the hill looks decrepit, with uneven hand-stacked stones and peeling red-painted pillars making up the exterior. As I move closer, the curiosities of the creation come into view—wheel rims used as windows, protruding colored glass bottles wedged between stones, and even petroglyphs etched on rock. 

Surrounded by saguaro cacti, and located mere minutes from the bustling city of Phoenix, sits the Mystery Castle—a stately stone structure with a stirring history. 

Sand castles

In the late 1920s, Boyce Luther Gulley spent many of his days on the beach with his young daughter Mary Lou, building sandcastles on the shores of Seattle. One day, Mary Lou—troubled by the tide washing away their castle creations—turned to her father and said, “Please, daddy, build me a big and strong castle someday that I can live in.”

When Gulley was diagnosed with tuberculosis in 1930 and given only months to live, he furtively fled his family and headed for a drier climate—desert air was believed to help dry moisture from the lungs of those afflicted with the infectious disease. Alone, he took solace in the foothills of South Mountain Park in Phoenix, Arizona. Memories of the days on the beach with his daughter were etched in his mind. Back home, his wife and daughter were left abandoned and unaware.

Driven by his daughter’s wish for a real-life sandcastle, Gulley began collecting anything he could find to use as building materials—mountain rocks, boxcar siding, remnants of old phone poles, car rims, and railroad tracks. He scavenged dumps and demolition sites and began building, never sure which day would be his last.  

Wacky and whimsical

The skeleton of a saguaro cactus sits in the centre of the guest house, the last of the rooms built on the property, and often the starting point of the cyclical castle tour. The two-level dwelling, featuring a slideaway bed on the ground floor, was built around a then-living cactus, which became the inspiration behind the small indoor garden that sits next to the sleeping quarters. 

“This is where we stay in the off-season, and it’s my favorite room in the house,” says the knowledgeable tour guide, one of a handful of on-site “castle keepers” who used to know Mary Lou personally. “It’s the coolest, temperature-wise, because a breeze often blows through the windows,” he says before moving to the next space.

The inside of the main building is a feast for the eyes, filled with folk art, kitschy cat decor, and eclectic antique collectables. In total, there are 18 rooms and 13 fireplaces, as well as a dungeon and a wedding chapel. Surrounded by stone, it’s evident that the main home can get quite hot during the warmer months. “We’re closed during the summer months because the heat can be overwhelming, plus the rattlesnakes on the property—you wouldn’t even believe the snakes that we’ve found here,” the guide says.

Gulley’s demise

As Gulley was working away on his eclectic desert palace, months turned into years. In 1945—15 years after the building began—the stately structure was finally complete. That year, Gulley wrote home, revealing his illness, and told his family to come visit him in Phoenix. 

Unfortunately, Gulley passed away before his family arrived for their long-awaited reunion. He had not revealed any details of the structure in his letters, hoping to surprise his daughter upon arrival. Knowing only that he had left them a home on the hill, Gulley’s wife and daughter moved to Phoenix, seeing the castle for the first time once they arrived.

Mary Lou and her mother lived on the property for many years, discovering many hidden treasures in the nooks and crannies of the space as the years passed. One particularly intriguing find was a hidden trap door, discovered under a metal statue of an alligator that sat near the entrance of the dwelling. Beneath it, they found money, letters from Gulley, and other trinkets. 

Mary Lou wanted to share her father’s story and her findings with the world, and in January 1948, Life magazine published a story titled, “Life Visits a Mystery Castle: A Young Girl Rules Over the Strange Secrets of a Fairy Tale Dream House in the Arizona Desert.” This article brought national attention to the mysterious site, and gave the structure its famous name: the Mystery Castle.

The princess’ castle

Inside the chapel—where weddings are still held—there is a floor-to-ceiling shelf with an assortment of single high-heeled shoes on display. Above them, a sign reads, “In the chapel, if the bride leaves one shoe then forever will the groom be true.” Mary Lou often opened up the chapel in her home for weddings, and with this sign encouraged brides to leave a shoe for good luck. “I think she just loved shoes and wanted to create a collection to keep for herself,” jokes the tour guide.

The master bedroom combines a wood-carved bed and dresser set, which once belonged to the first governor of Arizona, with red velvet loveseats that were scavenged from the red light district in Jerome. On the love seat sits two large doll figures—a bride and a groom—just two pieces of the puzzling decor found throughout the home.

Mary Lou and her mother began giving tours of the castle in 1948, and after her mother passed, Mary Lou continued to reside in the home until her own passing in 2010. 

“Mary Lou Gulley, resident princess and proprietress of the Mystery Castle, passed away November 3, 2010,” her obituary reads. “To ensure the Castle and the spirits of her father, mother, grandmother, uncle, and all other keepers of the castle would live on, Mary Lou formed The Mystery Castle Historical Foundation, a 501(c)(3) organization, to preserve and care for the castle when she was no longer able to do so.”  

Today, the castle remains intact, just as it was left when Mary Lou passed. Visitors can tour the site and hear the story firsthand. While guests are free to roam through the rooms and get an up-close look at their surroundings, one room remains inaccessible to visitors: the private bedroom of Mary Lou. She wanted to keep her personal sleeping quarters behind closed doors, and only a privileged few have seen it. 

If you go

Tours of the Mystery Castle are available without reservation from October to May, and are scheduled regularly from Thursdays to Sundays, 11 a.m. to 3:30 p.m. Admission is $10 per adult ($5 per child aged 5 to 12). The site is not wheelchair accessible and may be difficult for visitors with mobility issues.