Gaia - Port Wine Domains
Across the river, Gaia is married to Porto, being almost forbidden to visit one of them without crossing the bridge.
The riverfront of Gaia is an excellent place to a calm stroll, watching the good work done in Porto's waterfront, and choosing one of the many caves for a guided visit.
Porto wine cellars
If you want to taste and/or buy Porto wine, or searching for a wide view of Porto, head to Gaia.
Satisfied your purposes, the historic Porto is just there, across the old D. Luis bridge, built by Eiffel, as you may guess just by looking at it.
D. Luis Bridge
Does it belong to Porto or Gaia?
I mean: what is "the other side of the river"?
Until I decide it, I better mention the bridge in both pages. If you read about it in Porto's page just skip this. Or... go back there, and find how it looks more complex after a careful and detailed wine tasting.
And... don't drive back. Porto, in the other side, is at a safe walking distance.