There are gardens, and then there are the Forestiere Underground Gardens, where the first thing a visitor learns is that the earth can be an accomplice.

In Fresno, beneath the hard, sun-baked ground of California’s Central Valley, Baldassare Forestiere spent roughly forty years doing something that sounds less like horticulture than obsession: he dug downward. With a pick, shovel and wheelbarrow, the Sicilian immigrant carved rooms, passageways, courtyards, patios and grottoes into the unforgiving hardpan. He did not draw blueprints. He carried the architecture in his head. The garden came out of the ground as he imagined it, one scoop, one blow, one stubborn piece of sedimentary rock at a time.

Forestiere arrived in America from Sicily in 1901 with the conventional dream of becoming a citrus farmer. California, however, gave him a problem before it gave him an orchard. The Fresno heat could be brutal, and the hardpan beneath his property was difficult terrain for the citrus trees he hoped to cultivate. Rather than surrender to the soil, Forestiere went beneath it.

That decision changed everything.

He began excavating in 1906, eventually creating an underground world that was part residence, part agricultural experiment and part private mythology. The official Forestiere history describes a subterranean complex of patios, garden courts and grottoes, inspired in part by the ancient catacombs Forestiere had known from Sicily. He worked in his spare time for four decades, eventually excavating and planting more than 10 acres.

The result is difficult to classify because Forestiere himself seems to have ignored the need for classification. It is architecture without an architect, sculpture without a studio, agriculture without a conventional field. It belongs comfortably to the strange American tradition of artist-built environments: places made by people who simply kept making until the work became too large, too personal and too peculiar to be called a hobby.

The underground chambers offered another advantage. Beneath the California sun, the temperature was more forgiving. Forestiere planted orange, lemon and grapefruit trees underground, along with kumquat, loquat, jujube, carob, quince, dates and grapes. Some trees produced multiple varieties of fruit. Branches could rise toward openings in the earth, turning the subterranean chambers into improbable little orchards.

This is where Forestiere’s story begins to resemble something larger than an eccentric man’s solution to bad soil. The Underground Gardens belong to the history of Italian-American self-invention in California, a history in which labor, improvisation and imagination frequently overlap.

The most obvious companion is Simon Rodia’s Watts Towers in Los Angeles. Rodia, another Italian immigrant and self-taught maker, spent decades constructing a fantastical series of towers from steel, cement and found objects, decorating them with broken glass, pottery, shells and other fragments. Forestiere went down; Rodia went up. Forestiere excavated the earth; Rodia accumulated the neighborhood. Yet both men transformed ordinary California property into intensely personal environments. Scholars have specifically examined the Underground Gardens and Watts Towers together as expressions of the Italian immigrant experience and as examples of grassroots or outsider art.

There is something wonderfully Italian-American about that particular stubbornness. When the available materials are poor, make something from them. When the landscape refuses to cooperate, alter the landscape. When nobody gives you permission to be an artist, perhaps permission is beside the point.

California has other institutions that preserve the broader Italian-American artistic inheritance. San Francisco’s Museo Italo Americano, founded in North Beach in 1978, was established specifically to exhibit Italian and Italian-American art and culture and remains devoted to preserving that heritage. But Forestiere’s work occupies a different, stranger territory. His museum was the thing itself. His medium was dirt. His gallery had a ceiling of earth.

That distinction matters. Forestiere did not set out to make a monument to immigrant ingenuity. He was trying to make a life. The monument arrived accidentally, or perhaps inevitably, after decades of labor.

And there is the Tosches-like beauty of it: a man comes to California chasing oranges and ends up manufacturing a kingdom underground.

Today, the Gardens remain in Fresno, preserved and operated by the Forestiere family. The site was designated California Historical Landmark No. 916 in 1979 and is listed on the National Register of Historic Places. Visitors enter only by guided tour, descending into a place where the architecture remains inseparable from the hand that made it.

The experience is tactile before it is historical. Stone and soil replace polished floors. The air changes. Light appears in unexpected places. Passages narrow and widen. An arch leads somewhere another arch did not seem capable of leading. The surface world, with its traffic and pavement and commercial noise, becomes distant.

Forestiere’s great achievement may be that he did not conquer California so much as negotiate with it. He found the flaw in the ground and made it the foundation of his vision.

Above him was the California everybody knew: bright, hot, expansive.

Below was the California he invented.

And down there, in the cool dark, the garden kept growing.

Brian D’Ambrosio is the author of New Mexico Eccentrics and American Eccentrics, Mavericks, Misfits, and Visionaries. New Mexico Eccentrics: D’Ambrosio, Brian: 9781257192625: Amazon.com: Books