The dastardly super-villain's secret underground lair is a key part of many James Bond stories.
But it seems these subterranean complexes were not just the fantastical product of author Ian Fleming's imagination.
Newly-released papers have revealed details of Fleming's work with a real-life hidden city – in a genuine plot to save civilisation from evil.
The long-classified government documents relate to his plan for a labyrinthine network of 30 miles of tunnels inside the Rock of Gibraltar during the Second World War.
Fleming recruited six men for a remarkable mission – in which they were to be walled inside a hidden room deep inside the Rock, with supplies to survive for up to seven years in the event the Nazis conquered Gibraltar.
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14-09-21 PANORAMAdailyGIBRALTAR