Rather than following a set sightseeing schedule, create you own itinerary on a Porto sightseeing tour by hop-on hop-off bus. Your travel ticket, which lasts for either 24 or 48 hours, grants you access to two tour routes and gives you the freedom to disembark whenever an attraction captures your attention. Plus, on-board commentary means you'll be party to historical and cultural information that you're unlikely to find in the guide book.