Narrated tours of the inner and outer harbor. Specialty cruises, including lunch-hour cruises, whale-watching excursions and service to the harbor islands, are also available. Time and cost depend on trip. A 90-minute tour costs US$19 adults. 1 Long Wharf (Aquarium T stop on the Blue Line), Boston. Phone 617-227-4321. Toll-free 877-733-9425. http://www.bostonharborcruises.com.