I will arrive at about 2300 on 7th Mar and fly out at 1200 from OPO airport. I've never been to Porto before and have only been in Portugal (Lisbon) for an afternoon in summer a couple of years ago. This might be my only visit to this city.
What can I realistically see in this timeframe? I'm a foodie, and I'm most interested in sights that're unique to the location I visit. Not keen on clubbing or nightlife.