Actually you can visit underground tunnels in Fresno (just further away from downtown Fresno)...tho these tunnels have been closed on & off over the years:
It's the Forestiere Underground Gardens which were built over a 40-year period (1906-1946) by Baldasare Forestiere, designer and builder.
Here's one online description: "Located a short distance east of Highway 99, It is a complex of underground caverns, grottos, patios and garden courts encircling the underground home of Baldasare Forestiere. The various sections are inter-connected with underground passageways and promenades together with an auto tunnel approximately 800 feet long that winds through the gardens. These passageways are embellished with planters of various shapes and sizes, many with built-in recessed seats of hardpan, mortar and cement. There are columns, arches and domes of hardpan--a native sedimentary stone that is pervasive in the area. Some ceilings are vaulted and carved like inverted tea cups. Others have skylights adorned with redwood arbors and pergolas with cascading grapevines. Over his living areas, Forestiere built skylights that were covered in the winter with glass to keep out the rain, yet allow in natural light. To support the great mass of earth and to give permanence to his earthen sculptings, Forestiere used Roman arches, columns and domes. Hardpan, mortar and cement are used not only for structural purposes, but also for textural variety and beautification. A wide variety of trees were planted throughout the gardens, some of them rare. Some of the trees are planted as deep as 22 feet below ground level. Many citrus trees were grafted with a variety of citrus, one tree having some seven different varieties. Varieties that Forestiere planted include Almond, Pomegranate, Italian Pear, Bartlett Pear, Olive, Persimmon, Avocado, Loquat, Quince, Carob, Jujube, Arbutus, Black Fig, Tangerine, Grapefruit, Orange, Kumquat, Lemon, Date Palm and Mulberry. A small fish pond, crossed by a foot bridge, was created in the garden court off the kitchen and bedrooms. Also located in the gardens was an aquarium with a circular glass bottom through which tropical fish could be observed. On ground level there was a small lake, which has subsequently been filled in for a parking lot."
"Historical significance: The Forestiere Underground Gardens were designed and hand-sculpted by Baldasare Forestiere, a Sicilian immigrant. A vineyardist and horticulturalist, Forestiere began in the early 1900s to carve and sculpt a thoroughly unique underground retreat to escape the San Joaquin Valley's excessive heat. After nearly forty years with hand tools and persistent effort, he succeeded in creating a cool subterranean complex fashioned after the 'visions stored in my mind.' Forestiere worked without blueprints or plans, following only his creative instincts and aesthetic impulses. He continued expanding and modifying the gardens throughout his life. Baldasare Forestiere died in 1946 at the age of sixty-seven. After his death, the Underground Gardens were opened to the public as a museum."
(Oh, and needless to say, what can be admired today about Forestiere’s innovative design would never be approved in a significantly less libertarian culture of today...Today’s bureaucracy would have shut Forestiere down in two seconds!)
Nice post. Guess I should have read further. Thnaks.