Beneath almost a kilometre of Alpine rock, and some 180 metres into the Swiss mountainside, the bunker housing Radix Technologies' cloud datacentre was built to survive a nuclear holocaust.
As well as the natural barrier provided by the mountain, man-made defences such as reinforced concrete walls and steel doors weighing up to 30 tonnes make DK2 a datacentre site where physical information security hardly seems worth mentioning.
In its former life as the Swiss military's principal Cold War command-and-control centre, the installation could quarter about 1,500 personnel. Now it's home to three maintenance staff and racks of Dell servers running CA Technologies AppLogic cloud platform.
Switzerland is riddled with civil defence bunkers, like holes in a piece of Emmental. Of the country's 16,000 bunkers, most are far smaller than DK2's 15,000 square metres. "This is only one that combined such a big space and such a level of security," Radix Technologies chairman Stéphan Grouitch said.
When it was in military hands, its codename was K7. Its main entrance, seen above, lies up a track behind a low man-made bluff that keeps it concealed to visitors until the very last minute.
Toby Wolpe is a senior reporter at TechRepublic in London. He started in technology journalism when the Apple II was state of the art.