Several parks and nature preserves are found at various locations along the shoreline. Sightseeing boats depart from the downtown area. Commercial sport fishing and whale watching tours depart from Shelter Island. Ten museum ships call San Diego Bay home. They include the USS Midway, an aircraft carrier museum, and the Star of India, the oldest iron-hulled merchant ship afloat and the world's oldest active sailing ship. The Star of India and eight other ships and boats on San Diego Bay are the floating collection of the San Diego Maritime Museum; they are open to the public for a fee, and many are in sailing condition.