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The urban surface of London is no longer interesting enough for the ultra-rich; they're thus building downward.

As the Times reported this past weeked:

A Roman bath, a cinema for two dozen friends, even a subterranean tennis court—the super-rich are transforming their London homes, even if it means digging dozens of feet undergound.

The article goes on to describe how many of London's most financially advantaged residents, including oil tycoons and Indian steel magnates, have been "seeking permission to excavate under the garden... making space for a three-storey garage with car stacker, a swimming pool, a gym and a private home cinema." There are even "walk-in showers with waterproof television screens and glass walls that turn opaque with the press of a button, and cost £1,000 per square metre."

It's the urge toward subterranean architectural eccentricity, and it's transforming the very Earth beneath London.

[Images: London houses and their subterranean extensions; all photos via the Times].

For instance, we learn that "billionaire Russian oligarchs, private-equity traders and hedge-fund managers are engaged in a multimillion-pound game of one-upmanship as they vie with each other to dig ever bigger, wider and deeper extensions."

Indeed, "London’s super-rich are digging down and building outwards and upwards—and making use of the latest, priciest technology to do it."

Digging also helps them to avoid strict conservation laws, as the houses they've been extending into the Earth are usually listed structures: "Most houses now have more space below ground than above it, due to stringent planning regulations."

There are even "high-end builders," for whom business is booming, "who frequently dig down as far as 50ft to create new floors, basements and swimming pools, while the original house is propped up on giant steel pillars."

There's also quite a market for "adjustable-height swimming pool[s]" built far underground:

At the flick of a button—because everything is remote-controlled—the bottom can be raised or lowered by a giant hydraulic jack, forming a deep swimming pool for the heavyweight millionaire or a toddler-friendly paddling pool for his offspring.

Which is nothing:

One home in north London even has a bespoke chute covered in a special slippery paint, which enables the owner, who loves swimming first thing in the morning, but hates the fuss of dressing, to step out of bed and slide straight into the water a couple of storeys below.

Meanwhile, "a secretive hedge-fund tycoon" recently submitted a 168-page planning application within which he's requesting permission to build "a 16ft-deep swimming pool with high board"—among many other things—which, of course, will be underground.

"The super-rich are no longer demanding just luxury goods," we read; "they’re demanding a luxury lifestyle experience."

So while bored twentysomethings read Le Corbusier over and over again in roundtable discussions led by professors who would rather be elsewhere, the underworld of London is calling...

Read more at the Times.

(Thanks, Nicky! Earlier on BLDGBLOG: London Topological and Derinkuyu, or: the allure of the underground city).