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. Saint Petersburg Conservatory, Yusupov Palace, and Narva Triumphal Arch are well-known local landmarks worth a visit. You can watch performances at Mariinsky Theatre, Alexandrinsky Theatre, and Bolshoi Saint Petersburg State Circus if you're interested in local theater.