Alec Leamas, he was there when the Berlin Wall was built. He watched it going up so he told me, day after day, brick by brick, he said it terrified him, well it would. But he also said, there was a kind of war time thrill to it, he knew that feeling well enough, me too, his blood was up. They might have called this the Cold War but to Alec it was definitely war, hot and real. He ran agents both sides of that monstrous thing. "I wouldn't be surprised" he said "if it never comes down, but a network of agents, well, that can crumble at any moment".
John Le Carre - The Spy Who Came In From the Cold. Opening Lines from an Office Clerk, Radio 4 Adaptaion.BBC Radio Advert