they offer multi language tours which lasts about 3hrs. One gets to visit Porto mostly, from the Atlantic ocean where the faro is situated and where it is most modern to the old city center. Also you'll get to visit a porto wine lodge. all this including in the 30eur per person. The woman on the picture is Antoinetta, one of the guides.
Address:
RUA DELFIM DE LIMA 3551 4405-285 CANELAS Gaia Porto Portugal