
Mystery Castle is a beloved tourist destination in Phoenix. (Visitor7/CC BY-SA 3.0)
Mystery Castle and May Hicks Curtis House made the National Trust for Historic Preservation’s 2025 list of America’s 11 Most Endangered Historic Places.
Two iconic Arizona properties have earned spots on a prestigious national preservation watchlist, bringing both concern and hope for their futures. The May Hicks Curtis House in Flagstaff and Phoenix‘s Mystery Castle join the National Trust for Historic Preservation’s 2025 list of America’s 11 Most Endangered Historic Places, highlighting the urgent need to protect these cultural landmarks.
Historic Arizona landmarks receive national preservation attention
The designation comes at a critical time for both properties, with State Historic Preservation Officer Kathryn Leonard noting, “These designations are highly coveted, as they come with the National Trust’s resources to promote awareness about these unique, but imperiled, properties.”
Mystery Castle, an architectural marvel constructed between 1934 and 1945, stands as a testament to creative vision and desert adaptation. Built by Boyce Luther Gulley, this 18-room structure near South Mountain showcases a unique blend of folk art and organic architecture, incorporating elements from the surrounding Sonoran Desert. Visitors can learn more about this distinctive property on the National Trust’s website.

Mystery Castle is a beloved tourist destination in Phoenix. (Visitor7/CC BY-SA 3.0)
A race against time in Flagstaff
The May Hicks Curtis House faces immediate demolition risks unless preservation efforts succeed. This historic residence, built in 1913 along the original Route 66 alignment, belonged to the woman who sewed Arizona’s first state flag in 1911. Flagstaff officials have identified a temporary location and secured partial funding through the National Trust’s Preserve Route 66 Grant Fund to relocate the structure.
This recognition joins Arizona’s growing list of preservation priorities. In 2022 and 2023, Camp Naco in Bisbee and the Osterman Gas Station in Peach Springs also received this designation, with both properties showing positive progress in their preservation efforts.

The John Osterman Gas Station in Peach Springs, Ariz. (Rayc/CC BY-SA 3.0)
Since its inception in 1988, the National Trust’s endangered places list has highlighted over 300 sites. Most of them successfully avoided destruction through increased awareness and community support.
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This article first appeared on Good Info News Wire and is republished here under a Creative Commons license.
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