Porto is the main city of the North.
Porto is a small city with 200 thousand people, touristic and very typical. Everybody knows the view of Ribeira, with the coloured houses and the river Douro.
I really loved my experience there! Porto has everything you need: fantastic nature with the ocean and the main city park, nightlife, cultural places to visit.
From Porto it is quite easy to reach Douro Valley, well know for the Porto wine or Foz Coa, archaeological site with amazing paleolithic graffiti.