Beating Hitler with 3-D glasses
A BBC programme reveals how in WWII the Allies used 3D photos to thwart Nazi weapons of mass destruction before they could obliterate Britain.
Operation Crossbow saw Spitfire pilots taking plenty of photographs, which were then given to staff at RAF Medmenham to make sense of the clues hidden in them.
Hitler was pumping a fortune into his new-fangled V weapons in the hope they could win him the war - but Medmenham had a secret weapon of its own, a simple stereoscope which brought to life every contour of the enemy landscape.
Operation Crossbow is broadcast at 2100 BST on Sunday 15 May, BBC Two or catch up afterwards via iPlayer