A first-class tour guide in Rio is Martha, firstname.lastname@example.org. We took two four-hour tours in the city, one with a car and driver (which she supplied) and the second a walking tour of downtown. Both were excellent. She is a professional, licensed guide with an thorough knowledge of the city. You can set up your own destinations or she will suggest some. Her tours are also reasonably-priced compared to some others or the tours of the cruise ship which we were on. Highly recommended.