The apartment is located a few steps away from the Douro river, as well as from the terminal station of the street car, which will take you for a trip around the city.
Porto caves are located on the other side of the river, Vila Nova da Gaia, so you can reach them within 15-20 minutes on foot via the bridge of Dom Luís I.
Other than that, apartment is clean and nice. The bathroom is a bit small, but it was enough for our stay.