The idea of a billionaire bunker usually conjures up images of an underground mansion stocked for the end of the world. But deep inside a Swiss mountain, the new luxury is considerably less dramatic and arguably more useful: a private vault where the world’s wealthiest can keep their wine, art, gold, and Bugattis far away from the usual risks above ground.
In Switzerland’s Lungern, Brünig Mega Safe is developing a network of mega-vaults inside the Brünig massif, as reported by SRF. The underground complex is planned as a secure home for valuable possessions, including gold, cars, artwork and fine wines. The caverns will sit more than 100 meters below the mountain surface, with the project eventually expected to comprise roughly 20 to 25 individual spaces.
A private vault inside a Swiss mountain
The project is considerably closer to underground luxury real estate than a conventional storage facility. Buyers acquire an independent underground building right recorded in Lungern’s land registry, rather than simply renting a locker from a storage company. According to chairman Thomas Gasser, the right can even be mortgaged, effectively giving buyers a mortgageable, 99-year slice of a Swiss mountain.
That distinction also gives owners an unusual degree of control. Brünig Mega Safe is expected to manage the common perimeter, access routes and infrastructure, while the private cavern remains under the customer’s control. Owners can select their own security technology and decide how the interior is configured. A cavern can retain its raw rock walls or be transformed into something resembling a private gallery, with display cases, glass partitions, sculptural furniture and warm bronze and amber lighting.
The scale is designed for much more than watches and jewelry. Access tunnels are intended to accommodate trucks weighing as much as 40 tons, while a helicopter landing area provides another way to move particularly valuable or sensitive objects. A prospective customer has reportedly asked for space for 20 cars, while another wanted room for 100,000 bottles of wine. A separate wine merchant has discussed storing as many as 400,000 bottles in the broader Brünig Lagerhallen development.
Pricing reflects the exclusivity. Earlier plans put a 20-square-meter cavern at around CHF500,000 (about $615,000), while the current 75-square-meter option starts at CHF775,000 (roughly $960,000). A 210-square-meter cavern costs just under CHF1.5 million (about $1.8 million), with larger custom spaces available on request. Those figures cover the underground property right and core proposition, not necessarily an extravagant finished interior. Security systems, climate control, fire suppression, display installations and private rooms can all push the final cost considerably higher.
Where the mountain becomes the vault
The Brünig massif is particularly suited to the concept because the rock itself provides some of the environmental stability that collectors pay heavily to create elsewhere. The caverns naturally remain around 13°C throughout the year, making the conditions attractive for wine and certain collections. Serious collectors would still need to consider humidity, vibration, air quality, filtration, lighting and fire protection, meaning conservation-grade storage may require additional climate-control systems.
The mountain has already been extensively engineered. An underground shooting range, a fire brigade training tunnel, a restaurant and an explosives depot are among the facilities created there by Gasser Felstechnik, the family engineering business connected to Gasser. He first blasted into the mountain roughly 30 years ago when the company needed additional warehouse space.
The new vault system is planned across an underground area of roughly 200 by 300 meters. Its security proposition is deliberately discreet. Customers pass through a special checkpoint and multiple security checks before entering, while elite guards are expected to protect the facility around the clock. The access infrastructure includes a roughly 40-meter approach tunnel to the first customer’s cavern, and the escape route curves through the rock rather than following a direct line.
The clientele is equally discreet. Interest has reportedly come from Switzerland, including citizens living abroad, as well as Germany, Sweden and the United Arab Emirates. The largest cavern has reportedly been sold to an unidentified precious-metals dealer planning to hold gold and silver for its customers outside the conventional banking system. Brünig Mega Safe has also rejected several prospective projects after failing to establish the source of their money.
Construction finally moved forward after years of planning, with millions already spent on permits and assessments. The first underground work began in January 2026, following a ceremonial blessing of Saint Barbara, the patron saint of miners and tunnel workers. Initial construction and fit-out are expected during 2027, with customer use targeted for late 2027 or early 2028.
For billionaires, the appeal is remarkably simple. Instead of building another underground house, Brünig offers something rarer. It’s a private, highly secure piece of a Swiss mountain where a car collection, a cellar, or a priceless art collection can disappear from view without disappearing from ownership.
