This is Pionen White Mountains, the nuclear bunker in which WikiLeaks will locate some of its servers. It was excavated 30m underground in a rock hill in the centre of Stockholm, Sweden, during the Cold War.
Originally it was just a bomb shelter built in 1943. In the '70s, the Swedes turned the shelter into a full bunker, a civil defence centre that was going to hold an emergency unit of the Swedish government in the case of a nuclear war.
Now protected under 30m of rock and 0.5m-thick solid steel doors, it is the co-location centre of Bahnhof, a Swedish internet hosting company. Bahnhof further expanded the facilities, blasting new space for gas oil power plants extracted from decommissioned German submarines. In the case of cut in external power, those generators would kick in, keeping the servers running non-stop.
It also looks like they hired the same interior designer who decorated Batman's lair:
Apparently, the Bahnhof people are pretty happy to host Wikileaks in their ultra-secure bunker, safe from any political pressure and physical attacks. WikiLeaks is under attack by the US government for the publications of many of its secrets. Most recently, WikiLeaks released 100,000 internal military documents from the Afghanistan war.
Good luck getting there, Pentagon goons. Unless you invade Sweden or hire Lisbeth Salander. [Bahnhof]