Soleri ended up marrying the daughter of a client, and after a sojourn in Italy the couple returned to Arizona for good. He built Cosanti over a period of two decades, from the 1950s to the 1970s, as an expression of his belief that architecture could work in complete harmony with the natural environment (a concept he called “arcology”).

He, his staff, and Arizona State University students (plus a revolving cast of others who came to participate in workshops at Cosanti) constructed the buildings there by pouring concrete over pre-cast earthen molds. Once the concrete had dried, the molds were removed, leaving behind strong structures with a tactile, handmade quality.

The buildings’ proportions and placement were designed with the sun’s seasonal patterns in mind. This way, they gain extra sunlight and heat during the winter and provide shade during the warmer months. In some cases, they’re nestled into the earth to take advantage of cooler below-ground temperatures. It’s a perfect example of regional architecture, tailored to the particular qualities of the local climate and terrain.

Another major Soleri project is Arcosanti, an ambitious experimental community in the high desert of central Arizona. Construction started in 1970 on the 20-acre site, and Soleri continued to work on the master plan until his death in 2013 at age 93. Students and volunteers still live on the car-free property, working on silt-cast concrete buildings interwoven with artworks and terraced greenhouses. Thousands of tourists visit every year, drawn by the arcology concept and the fantastical appeal of a utopian town rising out of the desert.

The nonprofit Cosanti Foundation runs both sites, selling cast bronze and ceramic bells to help fund them. Cosanti, in Paradise Valley, and Arcosanti, in Yavapai County, are both open for tours. Visit the Arcosanti and Cosanti websites for more information.

For more on Cosanti, see Preservation magazine’s Fall 2015 travel story on Phoenix.