It is called Pionen White Mountains - located in an ex nuclear bunker deep below the bedrock of Stockholm city, sealed off from the world by entrance doors 40 cm thick (almost 16 inches).
Facts:
* Originally a nuclear bunker: The data center is housed in what was originally a military bunker and nuclear shelter during the Cold War era. The facility still has the code name from its military days: Pionen White Mountains.
* Located in central Stockholm below 30 meters (almost 100 ft) of bedrock: The facility has 1110 sqm (11950 sq ft) of space and is located below 30 meters of solid bedrock (granite) right inside the city.
* Fully redesigned in 2007-2008: Pionen was completely redesigned in 2007-2008 to become the data center that it is today. More than 4,000 cubic meters (141,300 cubic ft) of solid rock was blasted away to make more room.
* Can withstand a hydrogen bomb: The bunker was designed to be able to withstand a near hit by a hydrogen bomb
* German submarine engines for backup power: Backup power is handled by two Maybach MTU diesel engines producing 1.5 Megawatt of power. The engines were originally designed for submarines, and just for fun the people at Pionen have also installed the warning system (sound horns) from the original German submarine.
* 1.5 megawatt of cooling for the servers: Cooling is handled by Baltimore Aircoil fans producing a cooling effect of 1.5 megawatt, enough for several hundred rack-mounted units.
* Triple redundancy Internet backbone access: The network has full redundancy with both fiber optics and extra copper lines with three different physical ways into the mountain. Pionen is one the best-connected places in northern Europe.
* Work environment with simulated daylight and greenhouses: For a pleasant working environment the data center has simulated daylight, greenhouses, waterfalls and a huge 2600-liter salt water fish tank.
