A Labor of Love: Phoenix's Mystery Castle

The story behind the Mystery Castle

Nestled at the base of South Mountain, the 18-room Mystery Castle was built using a myriad of reclaimed, recycled and desert-originating materials. Boyce Luther Gulley’s venture to build a castle for his daughter Mary Lou began in 1930 and lasted an unexpected 15 years until his death in 1945. 

Caretaker Ramon Gastelum easily identifies his favorite room of the castle: “The Siesta Room.” Also known as The Saguaro Room, Gastelum enjoys napping on the pullout bed with the breeze flowing through the open window. The room was built around the spines of a saguaro cactus. Spines were also used in the furnishings of several stools and tables, and rims from the builder's Stutz Bearcat act as window frames.  

Mystery Castle

A Terminal Prognosis   

The story begins in the Pacific Northwest, where Boyce lived with his wife, Frances, and his young daughter, Mary Lou. During trips to the beach, Mary Lou would build sand castles, but as the tide rolled in and washed the castles away, her tears were always soon to follow. Boyce promised his daughter he would one day build her a castle that wouldn’t wash away. 

Diagnosed with tuberculosis and given only months to live, Boyce followed his doctor’s orders and traveled from his home in Seattle to Arizona—without the knowledge of his family. Frances eventually learned from Boyce’s doctor the reason for his departure, but despite letters sent throughout the years, Boyce never wrote back.  

A One-man Venture

“In Arizona, I think Boyce needed a reason for being and that morphed into the building of a castle for Mary Lou,” said Arizona State Historian Marshall Trimble.

According to the Mystery Castle Foundation, Gulley staked out unclaimed land in Phoenix for free by researching city documents at the library. 

“He had limited funds so he began scrounging around the Salt River Valley looking for materials to build his dream castle,” said Trimble. 

Mystery Castle

The living room was the first room Boyce built, and then he expanded from there. He worked without a floor plan; the longer he stayed alive, the larger the castle grew.

Boyce included a functional kitchen with a wood-burning oven and gas stove, and thought ahead to set the structure for indoor plumbing. A collection of tiny rooms to the west of the main castle was intended to be Mary Lou’s playhouse, though by the time Mary Lou arrived she was long past her childhood days. 

For building materials, Boyce often frequented salvage yards and took whatever he thought useful. He sourced hundreds of half-melted bricks, deemed as junk, from a local brickyard. These bricks, which are found throughout the castle, are now an expensive architectural element made popular by Frank Lloyd Wright’s use. 

The castle itself was a creatively cultivated project, and the furnishings were no less eclectic—according to the Foundation, the bed and dresser were given to him by Governor George W.P. Hunt, the first governor of Arizona, and Winston Churchill’s mother gave him two red-upholstered chairs. 

A Castle for Mary Lou

Before he passed, more than 15 years after setting the first stones for the castle’s foundation, the story tells that Boyce had his attorney notify his wife and daughter of a surprise he had left for them. The catch? His family needed to come to Phoenix to claim it. 

“They arrive to discover this mysterious-looking castle that he’s left for them, complete with 18 rooms, including a chapel, purgatory and a dungeon,” said Trimble. 

Mystery Castle

A note from her father asked Mary Lou to abide by one rule: not to open the 9-foot trap door inside the castle for two years or until she sold it—which ever came first. Mary Lou and her mother never left and, after two years, found in it two $500 bills, gold nuggets, the deed to the castle and a pile of letters Mary Lou had written her father. 

In 1948, Life magazine published a piece about the property—which is now listed on the Arizona Historic Register—that garnered attention and interest from the public. People began to visit, hoping for a tour, and Mary Lou was proud to show them around.  

Tour season has always begun October 1 of each year, said Gastelum, who has worked at the property since 1982 and, at one point, led some of the tours. He describes Mary Lou as being “a real tough lady, but real fair.” She sent Gastelum to school—first to learn English, then to get his diploma, followed by a college degree. 

Before her death in 2010, Mary Lou established the Mystery Castle Foundation in order to ensure that the property would remain unaltered and open to visitors. Today, Gastelum’s sons lead the tours, explaining the many unique intricacies of the castle and the story of a father’s love that built it all.