You'll want to browse the collections at Erarta Museum and Galleries of Contemporary Art, Alexander Pushkin Museum and Memorial Apartment, and C-189 Submarine Museum. Some landmarks that you won't want to miss include Strelka, Admiralty Building, and St. Isaac's Cathedral. You can watch performances at Mariinsky Theatre, Rimsky-Korsakov Conservatory, and Alexandrinsky Theatre if you're interested in local theater.