You might want to spend some time browsing the exhibits at Erarta Museum and Galleries of Contemporary Art, Russian Vodka Museum, or C-189 Submarine Museum. Russian Admiralty, St. Isaac's Cathedral, and Admiralty Building 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.