Cold War Weapons | Spies: Episode 1

The Cold War rivalry between the USA and the USSR not only promoted the creation of sophisticated weapons but entailed an unprecedented hunt for information. To know what was happening behind the Iron Curtain, CIA and British MI6 dug an underground passage half a kilometer long near the border of East Berlin. The intelligence officers spent almost a year creating this spy tunnel. They aimed to tap into secret communication lines used by the leaders of the Soviet military and employees of the Soviet embassy. However, Soviet intelligence services knew about this tunnel even before their Western counterparts began building it. How did that happen and why was the KGB considered perhaps the most technologically advanced special service?