A great day side trip from Porto is to take the #1 tram from below St Francis cathedral along the Douro river towards its mouth where it meets the Atlantic Ocean. It costs 3 euros and at the end of the line you can walk along the boulevard, past the fort and reach the ocean beach. In a back street from the beach is a very authentic Portuguese restaurant called Popular da Foz. The street is called Rua Senhora da Luz and the owner speaks English and has multi language menu. The food is reasonably priced and for a true Porto experience try the Francesinha. Very filling and tasty, similar to a Crocque Monsuieur, with a Porto twist about 9 euros.