You'll want to browse the collections at B-413 Submarine Museum, Bunker Museum, and Kaliningrad Regional Museum of History and Arts. Some landmarks that you won't want to miss include Brandenburg Gate, Ruins of Koenigsberg castle, and Honey Bridge. You can watch performances at Kaliningrad Regional Musical Theatre, Music theatre on Basseynaya, and Queen Louise Kirsch Puppet Theater if you're interested in local theater.