There is no question you enjoyed your walking tour of Cartagena. If you have extra time, extend your pleasure by sea. A popular option is a sightseeing trip around the bay. One of the best operators is Barco Turístico. The one-hour ride departs from Muelle de Alfonso XII and shows you many historic sites along the coastline. You can also hop off to explore the Christmas Fort (Fuerte de Navidad). Perhaps a half or full day of fishing is your idea of fun. Also consider renting a motorboat, sailboat or houseboat for an afternoon of adventure. Or lodge in a catamaran sailboat.