You might want to spend some time browsing the exhibits at Erarta Museum and Galleries of Contemporary Art, C-189 Submarine Museum, or Pushkin Flat-Museum. Strelka, Menshikov Palace, and Russian Admiralty are monuments to see when you're exploring the area around Tuchkov Bridge. You can catch a show at Mariinsky Theatre, Alexandrinsky Theatre, and Oktyabrskiy Big Concert Hall.