You might want to spend some time browsing the exhibits at C-189 Submarine Museum, Erarta Museum and Galleries of Contemporary Art, or General Staff Building. Grand Choral Synagogue, Saint Petersburg Conservatory, and Yusupov Palace are well-known local landmarks worth a visit. You can watch performances at Mariinsky Theatre, Rimsky-Korsakov Conservatory, and Alexandrinsky Theatre if you're interested in local theater.