 In the harbour, as well as excursion and fishing boats, is the British submarine HMS Otus, a museum piece, as is the coastal sailing cargo boat, "Annemarie", which was converted in 2007 into a passenger boat.The Alaris Butterfly Park ("Alaris Schmetterlingspark") in Sassnitz has been open since July 2003.The park is home to hundreds of free-flying butterflies in a tropical environment.