Two Arizona Sites Named Among Nation’s Most Endangered

And Losing Them Would Erase Irreplaceable History

Two Arizona landmarks made national news in May 2025, but not the kind anyone wanted.

The National Trust for Historic Preservation named the Mystery Castle in Phoenix and the May Hicks Curtis House in Flagstaff to its annual list of America’s 11 most endangered historic places.

The list spotlights sites at risk of vanishing forever, and these two tell stories Arizona can’t afford to lose. One represents folk art and desert survival.

The other honors the woman who stitched the state’s identity before statehood even happened. Both need money and community support right now, because once they’re gone, no amount of regret brings them back.

Mystery Castle Proves Desert Innovation Works

Boyce Luther Gulley built the Mystery Castle between 1934 and 1945 using materials most people threw away.

He collected stone from South Mountain, salvaged telephone poles and railroad ties, gathered car parts and wagon wheels, and mixed his mortar with goat milk using techniques he learned from Native Americans.

The 18-room structure has 13 fireplaces, floating stone staircases, and Pyrex dishes set into walls as windows. He used no plans, no permits, and had no formal training.

The castle sits in the foothills of South Mountain Park and has survived nearly 90 years of harsh desert weather because Gulley understood how to work with the environment instead of against it.

A Dying Man Built It for His Daughter

Gulley was diagnosed with tuberculosis in 1927 and left Seattle without telling his wife or young daughter Mary Lou where he was going.

He disappeared for years, sending occasional letters but never explaining why he left.

He had promised Mary Lou he would build her a castle that waves couldn’t wash away, like the sandcastles they made at the beach. In Phoenix, while his health declined, he kept that promise.

He wrote home in 1945 to tell them about the castle, but he died before they arrived. Mary Lou was 22 when she saw it for the first time.

She and her mother moved in and ran tours until Mary Lou’s death in 2010.

Vandals Destroyed Over $100,000 Worth of History

On March 5, 2022, someone broke into the Mystery Castle and went room to room smashing everything.

They kicked out window frames, shattered 20 doors, destroyed railings and furnishings, and ransacked even Mary Lou’s private bedroom that was never part of the tour. The damage topped $100,000.

Phoenix police found no suspects. The castle closed and never reopened.

The Mystery Castle Foundation, which took over after Mary Lou died, operated solely on tour income. Without tours, they had no money for repairs.

Break-ins continued. The building deteriorated.

The foundation couldn’t afford to maintain or operate it anymore.

The Foundation Applied to Tear It Down

In November 2023, the Mystery Castle Foundation filed for a demolition permit with Phoenix. They said they had no other options.

The city denied the permit for one year to give preservationists time to find solutions. That year expired in November 2024.

The foundation says publicly they don’t want to demolish the castle, but they filed the permit knowing it would force conversations about funding.

Phoenix hired consultants to assess the building and recommend repairs. Preservation groups formed to save it.

Without major funding and a plan to reopen it, the castle sits empty and at risk. If demolished, Arizona loses a one-of-a-kind example of folk architecture and adaptive desert building.

May Curtis Sewed the First Arizona Flag

In 1911, May Hicks Curtis was 23 years old and living in Flagstaff when her fiance Frank Curtis and Arizona National Guard Captain Charles Harris asked her to make a flag.

Arizona was still a territory, but the rifle team needed a flag for an upcoming competition. May designed and sewed it herself.

The flag featured a copper star on a blue background over red and gold rays representing Arizona’s sunset. Arizona became a state in 1912, and her flag became the official state flag.

That original flag is now in the Arizona Capitol Museum. May was more than the woman who made a flag.

She was a college graduate, assistant postmaster, and photographer who helped create the largest collection of pre-World War II photos of Flagstaff.

She Lived in a House Along Route 66

May built the house in 1913 at 123 South Leroux Street, just off the original 1920s alignment of Route 66. She lived there for decades with her first husband Frank Curtis and later her second husband Jonathan Hill.

Next door, she and her mother ran two boarding houses that likely served early Route 66 travelers passing through Flagstaff. May was active in the Flagstaff Women’s Club and the Arizona Historical Society.

She devoted her life to improving her city and state. The house where she lived and worked is the property most closely tied to her legacy.

It was listed on the National Register of Historic Places as a contributing structure to the Southside Historic District.

Flagstaff Moved the Entire Building Overnight

Developers bought the land where the house sat and planned new construction. The only way to save the house was to move it.

Flagstaff took ownership and hired a crew to relocate the building.

Workers removed the chimneys, lifted the 1913 structure onto steel beams, and loaded it onto a truck.

Just before midnight on a Tuesday in May 2025, the house rolled down South Leroux Street and across the Rio de Flag channel. Arizona Public Service lifted power lines.

City workers blocked intersections. The house bottomed out crossing the creek, so crews used wooden blocks to lift it higher.

By early morning, the house reached a temporary storage yard at the city’s recycling center. Flagstaff is now searching for a permanent location and raising money to rehabilitate it for community use.

Camp Naco Got $8 Million After Making the List

Arizona has seen this work before. Camp Naco in Bisbee, a military camp built in 1919 to protect the Mexican border during the revolution, made the 2022 endangered list.

The camp housed the 9th and 10th Cavalry Buffalo Soldiers and is the last of 35 border camps still standing. After 22 years of advocacy got nowhere, the endangered designation changed everything.

In October 2022, Arizona awarded Camp Naco $4. 6 million from American Rescue Plan Act funds.

In January 2023, the Mellon Foundation added $3. 5 million.

The money is stabilizing 23 adobe buildings and creating museum space to honor Buffalo Soldier history. The endangered listing brought attention that brought funding.

Osterman Gas Station Got Route 66 Grants

The Osterman Gas Station in Peach Springs made the 2023 endangered list.

Built in 1929 from a Sears concrete block kit, the station served Hualapai Tribe members and Route 66 travelers for decades. By the time Interstate 40 bypassed Peach Springs in 1979, business slowed.

The station closed in 2005. A 2021 windstorm tore off the roof and knocked down the tree that shaded the bus stop.

After the endangered designation, grants started arriving. The Historic Route 66 Association of Arizona gave $45,000.

Arizona State Parks provided American Rescue Plan Act money. Workers are now replacing walls and the roof.

The Hualapai Tribe is developing plans to reopen it as a museum, gift shop, or community space.

Once Gone These Stories Disappear Forever

The Mystery Castle shows how to build in the desert using local materials and traditional techniques. If demolished, that knowledge vanishes along with one of Arizona’s most unusual roadside attractions.

The May Hicks Curtis House honors the woman who gave Arizona its symbol before statehood. Move it to a good location and rehabilitate it, and future generations learn her story.

Let it rot in storage, and people forget she existed. Buildings hold history in ways plaques and books don’t.

Stand inside the Mystery Castle and you understand Boyce Gulley’s determination. Walk through May Curtis’s house and you connect to Arizona before it was Arizona.

Lose the buildings, lose the connection. Some things you can’t replace once they’re gone.

Visiting Mystery Castle, Arizona

The Mystery Castle is located at 800 East Mineral Road in Phoenix at the base of South Mountain. As of December 2024, the castle remains closed to the public following vandalism damage in 2022.

Check the Mystery Castle Foundation website or social media before visiting, as no reopening date has been announced. When it was open, tours ran October through May, Thursday through Sunday.

Admission was around $10 for adults. The site is listed as a Phoenix Point of Pride.

Visiting May Hicks Curtis House, Arizona

The May Hicks Curtis House is currently in temporary storage at the Flagstaff recycling center on Butler Avenue and is not open to public viewing.

The City of Flagstaff is searching for a permanent location and raising funds for rehabilitation.

Once relocated and restored, the city plans to use it for municipal offices or community space with public interpretation of May Hicks Curtis’s contributions to Arizona history.

Check the City of Flagstaff website for updates on the house’s future location and public access.

This article was created with AI assistance and human editing.

Read more from this brand:

• Trump wants new ballroom bigger than the White House; clashes with architect
• Why a father fled Seattle to build his dying promise in the Arizona desert
• Montana ski town is begging Canadians to come back with discount passes