Under the communists, St. Petersburg was not a popular city for large part of the last century. Stalin saw it as the power base of one of his main rivals, the murder of whom led to the beginning of the Great Terror. The city, while accepting a change to its new name of Leningrad, refused to accept other changes, like changing Nevsky Prospect to Lenin Street -- Nevsky was a monk, not a hero the leaders of a state with no god wanted folk remembering. Stalin also tried to move the centre of the city from nevksy down to the south -- get the metro to Moskovsaia station and have a look around, this was to have been part of the new centre of Leningrad. Moskovskaia is also good as you can then walk south a bit further, or get a bus (turn right as you come out of the station) to the War Memorial, which marks where the Nazi forces reached in their blockade of the city. There's a museum under the monument, in the middle of a roundabout, which includes things like Stravinskii's violin. Moskovskaia is also the station from which you can get a bus to the airport -- number 13.