This Invisible Home in Monaco Was Built Into a Cliff

By Elizabeth Fazzare

Photography by Loïc Thébaud

On the French Riviera, the principality of Monaco is known for its stunning seaside vistas, lavish lifestyles, and Belle Époque architecture. Though its waters call to many as a destination for boating and sports, a dense urban landscape wins out over nature once on shore. Now, behind one of the country's few remaining natural rock formations is a surprising discovery: a three-bedroom home designed as a sustainable and sensitive addition to its largely built environment.

Nestled between blocks of apartments and villas, the rocky promontory was once part of a fortified protohistoric village. A longtime client called Paris-based architect Jean-Pierre Lott and challenged him to turn it into a private home with as little physical disturbance as possible, to both the site and the Earth. "The project builds within the rock mass to bring the house into the environment and not to impose itself on it," says Lott, who completed the 5,382-square-foot Villa Troglodyte in 2019. Using a subtractive design methodology, he carved the home's four levels out from the rock's interior, leaving its vegetated cliff face mostly undisturbed, save for the doorway, garage, terraces, and windows, all of which are deep set to lessen their visual presence.

An exterior view of the home shows how the property recedes into nature.

The home totals 5,382-square-foot and includes three bedrooms.

Inside, the latest in sustainable design technology is used to build and power the cave-inspired home, which is naturally lit by a large skylight through all floors and fueled by energy both from a slate of solar panels and geothermal wells. A gray water recycling system supplies the toilets and washing machines. Concrete, steel, and rock create the main structure and are left exposed where used. Every material was selected strategically for its sustainability: Renewable cork forms the insulation, non-toxic limewash paint covers solid walls, the wood floors are made of reclaimed piles from an oyster farm. "The house is a veritable environmental laboratory where high-performance technical solutions for energy efficiency, carbon footprint control, and environmental neutrality are tested," the architect says.

A series stairs are reflected in the all-glass banister, creating the feel of a labyrinth.

Natural light floods the space through a series of sky lights.

Construction was a veritable feat in preservation and innovation. The existing rock was preserved up to the ground floor level; the home was then carved inside it, and the upper part of the rock was reconstructed exactly as it was before using a thin layer of sculpted concrete, Lott reveals. Visitors enter the villa via a skybridge over the lower level swimming pool, designed in an organic shape and meant to evoke an underground lake. (Its craftspeople were chosen for skills gleaned in their daily profession—as restorers of prehistoric caves.) Above, the vertically oriented house is accessed by steel staircase, and revealed through glass panels replacing traditional walls to allow light to penetrate each floor. Each bedroom has its own bathroom and terrace, where large sliding glass doors provide interior sunlight and frame views outside.

The home has several private balconies overlooking Monaco.

A peek into the sleek kitchen.

Though building this home inside this specific rock was a very site-specific exercise, Lott hopes Villa Troglodyte's lessons in sustainable design can be a global model. "The construction of the villa raises the question of the relationship of man to nature, of nature to culture," he says. If nothing else, it proves that architectural creativity knows no bounds.