The lone plaque memorializing Washington's spy history is at the Georgetown restaurant Au Pied de Cochon, stating "Yurchenko's Last Supper in the USA...Nov. 2, 1985." It commemorates KGB spymaster Vitali Yurchenko, who defected, then had second thoughts over dinner with a CIA agent. He slipped out the restaurant's back exit, and reappeared two days later claiming he had been kidnapped, drugged and taken away against his will.
Au Pied De Cochon
The trouble with spying is that it's a terribly time consuming process relying on electronic surveillance or using people to either break in or secretly pass on confidential information. The CIA realized that both of those approaches were not only fraught with inefficiencies, so why not remove man and machine out of the equation?