You might want to spend some time browsing the exhibits at Erarta Museum and Galleries of Contemporary Art, C-189 Submarine Museum, or Anna Akhmatova Literary and Memorial Museum. Menshikov Palace, Russian Admiralty, and St. Isaac's Cathedral are landmarks that you won't want to miss. You can watch performances at Mariinsky Theatre, Alexandrinsky Theatre, and Oktyabrskiy Big Concert Hall if you're interested in local theater.