This 2017 photo shows the man on the right, identified by local Hong Kong media as former CIA agent Jerry Chun Shing Lee, standing in front of a member of security at the unveiling of Leonardo da Vinci's "Salvator Mundi" painting at the Christie's showroom in Hong Kong.
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A monitor outside a courtroom shows Sergei Skripal speaking to his lawyer from behind bars in Moscow in 2006. Skripal is a retired Russian colonel recruited by British intelligence in the mid-1990s.
In 1955, British spy Kim Philby denied working for the Soviet Union. Eight years later, he defected to Moscow. He went on to speak to Stasi agents in East German, in an event that was captured on film.
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The villa that allegedly belongs to the NSA in Vienna. News outlets, the government and opposition parties are battling it out over allegations that the stately villa in a leafy Vienna district served as a sophisticated a U.S. intelligence listening post keeping tabs on most of Vienna.