You might want to spend some time browsing the exhibits at Cruiser Aurora, Museum of the Defense and Siege of Leningrad, or Pushkin Flat-Museum. Peter and Paul Fortress, Palace Embankment, and Strelka are monuments to see when you're exploring the area around State Museum of the Political History of Russia. You can watch performances at Alexandrinsky Theatre, Oktyabrskiy Big Concert Hall, and Mariinsky Theatre if you're interested in local theater.