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, Alexandrinsky Theatre, and Bolshoi Saint Petersburg State Circus if you're interested in local theater.