So where do you store thousands of confidential emails and documents that have set the world on its ear? In a secret Cold War bunker in Sweden. The Pionen Data Centre is 30m underground - a huge cave drilled into granite under the Vita Berg Park in Stockholm, Sweden.
And it has German U-boat engines as back-up generators. The bunker was re-opened in 2008 and is the work of Swedish architects Albert France-Lanord who were inspired by James Bond movie sets.