Porto:
WikiTravel - Porto

General
https://www.thecrazytourist.com/25-best-things-porto-portugal/

Airport:
https://en.wikipedia.org/wiki/Porto_Airport
http://www.porto-airport.com/

Tourism:
https://www.accorhotels.com/gb/travel-guide/porto/index.shtml
Livraria Lello: https://www.livrarialello.pt/en-us/
Fundação de Serralves: https://www.serralves.pt/en/museum/the-museum/

Porto wine caves:
Caves Cálem: https://www.tripadvisor.com/Attraction_Review-g580268-d243625-Reviews-Porto_Calem-Vila_Nova_de_Gaia_Porto_District_Northern_Portugal.html
Caves Calém at Gaia waterfront is one of the most famous and most visited cellars for wine tours in Porto. Visits to Caves Calem include a guided tour to the cellar and its ancient traditions, followed by a tasting of Port wine - white and special reserve.
Burmester Porto Wine Cellars and Wine Tasting: https://sogevinus.com/tourism/burmester-cellars/
Burmester wine cellars are located in Gaia by the bottom deck of Luiz I bridge. There are guided tours of the cellars, filled with history and interesting stories.

Shopping:
Mercado do Bolhão
Norte Shopping
Cidade Bom Sucesso
Arrábida Shopping

To see:

Porto
Clerigos Tower
Casa da Música
Serralves Park/Museum
Bridges Cruise onboard with ‘Rabelos Boats’
Palácio da Bolsa
Porto Cathedral

Lisbon
2h by high-speed train