Question: Who was the surgeon's son turned spy sent to St Petersburg, Russia's second largert city?
Sentence (from "Saint Petersburg"): In 1914, the name was changed from Saint Petersburg to Petrograd (Russian: Петрогра́д ; ] ), in 1924 to Leningrad (Russian: Ленингра́д ; ] ), and in 1991 back to Saint Petersburg.
Relevant evidence: No