The first thing Jon Karlung remembers about the sealed room inside the nuclear bunker he renovated six years ago is its murky odor. It smelled like a crypt. Then, looking around, Karlung's crypt felt more like a flashback machine. "It looked like something from childhood," he says. "With these '70s green and orange colors. It was like a time capsule that had not been renovated or changed since the 1970s." That bunker, called Pionen White Mountains is located just south of Stockholm. Nearly 20 years after Sweden's Civil Defense decommissioned it, Karlung converted it into a data center. A few years ago, it was briefly the most famous data center in the planet -- home to WikiLeaks. Read More: The Most Wonderfully Ridiculous Movie Computers of All Time Return of the World’s Most Wonderfully Ridiculous Movie Computers Drones, Caves, and Toilets: When Data Centers Go RogueAnd what a home it was; Karlung's internet service provider, Bahnhof, took the nuclear bunker idea and went all-in. It now looks like a cross between a James Bond lair and the eco-pod-filled spaceships of the 1972 cult sci-fi film Silent Running. Karlung, who worked briefly as a film archivist before getting into the data-center business, says that he immediately thought of putting plants in the underground caves to capture the computers-meet-plants vibe of Silent Running. "It had this mood and it had this atmosphere that I liked. It captures this atmosphere of growing something from outer space." The bunker is owned by the City of Stockholm, which had previously leased it out for the occasional art party or rave, and even -- once -- a wedding. But Bahnhof felt that it could work as a data center -- it was big, had power, and was very centrally located, just a few kilometers from Stockholm's downtown. And it was secure. Located 100 feet below ground and shielded by 16-inch-thick metal doors, Pionen was built to survive a hydrogen bomb. It took more than two years to blast out the 141,000 cubic feet of extra space that Bahnhof needed to squeeze its backup generators and server racks into the caves. It was an intense job. At one point a dynamite blast shot stone through the front door and into a car parked in front of the data center; nobody was injured. And if you're lucky enough to get your own tour of the data center, you can see a decommissioned Dell PowerEdge web server, once used by WikiLeaks, on display at a Bahnhof bar (yes a real bar) in another of its Stockholm data centers. There's still a second WikiLeaks server, a database system that's offline in the Pionen data center. Bahnhof says it has about 200 Gb of data onboard. Most often data centers are built in boxy warehouses, so Bahnhof stands out as perhaps the world's most stylish. In fact, it inspired Cisco IT Architect Douglas Alger to write a book on the world's best-looking data centers. "The idea that people were sitting in a design meeting and said, 'what we need for our data center is waterfalls,' that must have been a very fascinating discussion," Alger says. We have a bit of a soft spot for movie supercomputers and James Bond lairs here at Wired, so we asked Karlung for some photos. He gave us a lot, including shots of the far-out data center, and a few never-before-seen pictures of the remnants of the old nuclear bunker that Bahnhof found when they moved in. Above: This glass-walled conference room overlooks Pionen's data-center racks. It doubles as a great place to trap Loki, should he ever drop by and try to destroy the planet. All data center photos: Bahnhof

Bahnhof kept the Pionen name when it moved into the bunker. It also kept an old sign from the nuclear bunker near the entrance. It reads, "These doors should be locked at DEFCON1."

A 1970s telephone, an ashtray, and blueprints. These may look like Hollywood art department props used in the underground lair scene of a Roger Moore film, but in reality, they're just stuff that the Bahnhof crew found when they moved in.

A Pionen storage area, piled high with cans of gas masks. This was cleared out when the data center moved in.

Once the most-wanted server on the planet, this WikiLeaks system is now a bar ornament at the nearby Bahnhof Thule data center. Customers who want to visit the Pionen underground lair wind up their tours with a free beer here at the Thule Bahnhof Bar.

More 1970s detritus. Here's an old radio that Bahnhof found in the nuclear bunker's communications room.

Bahnhof Chairman Jon Karlung says the plants and waterfalls were inspired by the 1972 Bruce Dern film Silent Running. In the movie, Dern plays a botanist circling Saturn in a space station filled with biodomes, in charge of preserving the last line of plants salvaged from a despoiled planet Earth.

In Silent Running, Bruce Dern goes on a homicidal rampage after being ordered to destroy space-pods filled with plants. The film was directed by 2001: A Space Odyssey special effects guru Douglas Trumbull.

A shower. Karlung says this was designed to remove radioactive particles from visitors after a nuclear detonation.

Radiation-cleansing showers, James Bond style. This is how Sean Connery and Ursula Andress de-radiated in 1962's Dr. No

It's a bit of a tricky job to operate backup diesel generators 100 feet beneath the surface of a mountain. Bahnhof uses two Maybach submarine engines to provide backup power.

The nuclear bunker's old diesel generator, found by Bahnhof when they moved in. Apparently this old clunker wasn't up to the task of keeping a modern data center up and running.

A confession: We're not exactly sure what these '70s-looking gauges are for. Karlung thinks they may have been used to measure air quality in the bunker.

The entrance to Pionen as it looked when Bahnhof took over.

The bunker a few years back, after a bit of dynamite blasting.

A hand-cranked air pump. If the bunker's electric fans failed, this was designed to keep air flowing into the bunker.

Your basic 1970s equipment control panel. Another relic of the nuclear bunker era.

Here you get the full effect of the Pionen network operations. The plants here are real, kept alive by grow lights. By giving Pionen this futuristic feel, Bahnhof says employees are happier and more productive -- they like working in a cool space. Strangely, this mountain stronghold has more of a human touch than the average warehouse data center, Karlung says.