“No house,” wrote Frank Lloyd Wright, “should ever be on a hill or on anything. It should be of the hill. Belonging to it. Hill and house should live together each the happier for the other.”
At his most famous house, Fallingwater (1937) on the Bear Run river in Pennsylvania, Wright allowed the rocks of the hill to come inside, creating a fireplace from the boulders of the landscape in situ. It was a remarkable idea, an attempt to integrate the heart and hearth of the house with the landscape, to suggest that this was almost a natural extrusion of the geology.

It inspired many others to look carefully at the rocks and boulders on the sites of homes to see whether the usual approach of blowing them up and carting away the bits may, in fact, have been robbing these sites of the character that made them so special.
After the second world war in particular there was a revival of rubble: what architectural historian Jeffrey Lieber has called “Flintstone modernism”. You notice it in Los Angeles villas but also in the rough stone walls of mid-century bungalows in New York’s Queens or the outer suburbs of London, and even in the fake stone cladding applied to British Victorian terraces.

You notice it, of course, in the 1960s Flintstones cartoons themselves, where mid-century style was lampooned in a Stone Age setting. But it also appeared in the most crisply modernist houses, where architects allowed huge boulders to penetrate the perfection of their glass walls, anchoring the otherwise lightweight buildings to their context, to the landscape.
Most famous, perhaps, is Albert Frey’s remarkable Palm Springs House, built for himself in 1964. Perhaps Frey’s memories of the mountains of his Swiss childhood impinged on his design, but the way the huge rock collides with, and is then subsumed by, the super lightweight, almost ad hoc, architecture remains a revelation.

Also in Palm Springs is John Lautner’s Elrod House (1968) with its domed central space and rocks looming up between the living and bedroom spaces. The house is dramatic enough already with Lautner’s signature spaceship styling, but the rocks embed it in the landscape and focus the eye over the views of the Coachella Valley and the stark mountains beyond.
These houses seemed to communicate something. Beautifully photographed and atmospheric, they exuded a pioneer spirit of living with the landscape and still exert a powerful pull on architects. Chilean Smiljan Radić never passes up the chance to incorporate a boulder into his enigmatic structures (his 2014 Serpentine Pavilion in London sat on what looked like Neolithic stones) and Czech practice Uhlík Architekti’s charismatic little forest retreat (2013) in the woods of central Bohemia show the boulder’s reach as an idea and a kind of surreal gesture. Think of the boulders that pop up in the work of Magritte or Dalí: always out of place, always arresting.

Olson Kundig’s The Pierre (2010) on Washington state’s San Juan Islands incorporates the huge rocks that seem to be squeezing its concrete walls from all sides. Here too the rock spills into the rooms in the form of fireplaces, but it also appears as walls and even washbasins. Some rooms are cut into the rock, the drill marks visible in skylights, so that the spaces resemble the inside of a quarry.

Charles Foreman Johnson designed his Boulder House in 1983 in a more literal Flintstones style, an architectural approach that builds on native techniques in the Sonora desert in North Scottsdale, Arizona. Here, the architecture plays second fiddle to the rocks.
Built in between an outcrop of rocks, the house is defined by its billion-year-old boulders bulging and undulating through the interior. It is thought the rocks had been inhabited by native Americans using the shade and thermal cooling. Rather than contrasting a light, modern idiom with the solidity of the rocks, Foreman responded with more organic forms, adobe walls and curved, sculpted openings.
But the curves are nothing compared with Kendrick Bangs Kellogg’s High Desert House (1993). Looking like an armadillo emerging from the rocks in California’s Joshua Tree desert, it is one of the most striking and original of the US organic houses. Rocks rise up through the floor, while the overlapping plates of concrete above let light in through the cracks between them. Combining a touch of Sydney Opera House with a dash of New York’s TWA terminal (now a hotel), this is where the Flintstones meet the Jetsons.

It seems mostly an American phenomenon — a search for rootedness, for an attachment to the elemental, perhaps as a response to a nation still so often seemingly in flux. And, like those massive boulders, it is an architectural device that is unlikely to disappear any time soon.
Photographs: Western Pennsylvania Conservancy; Christopher Little/Western Pennsylvania Conservancy; Alamy; Jeff Marquis via Flickr; Benjamin Benschneider; Joseph via Flickr