The historic centre of Oporto is located along the hillside of the northern bank of the Douro River, just a few kilometres from the Atlantic coast. In guidebooks, the historic centre is often subdivided into an upper town with the cathedral at the highest point and a lower town, the Ribeira quarter. But that’s only half the truth. Actually, Oporto is an up-and-down-up-and-down city, a proper visit of the core zone can be an exhausting exercise.
In May 2018, I spent two and a half days and three nights in Oporto. I had accommodation in Vila Nova de Gaia, just two hundred metres from the Ponte Dom Luis I. So I had several times the opportunity to enjoy the beautiful view of the old town from the top level of the bridge or from the opposite bank of the Douro. It is one of the most picturesque urban landscapes I’ve visited so far, almost a bit corny (take my photo as a proof): the river, wooden ships with old wine barrels, lines of colourful houses one above the other along the hillside.
But that’s just the first, superficial impression, on closer inspection you get a different view. Some reviewers described Oporto as raw and dilapidated, I agree, and I also agree that this contributes to the special atmosphere. When I visited Oporto in May 2018, there were numerous construction cranes and scaffolding, many façades looked newly renovated, especially in the main streets such as the Rua das Flores. Obviously things have improved in recent years and Portugal is slowly recovering from the impact of the banking crisis ten years ago. But there is still a lot to do, when you take a look in side streets a bit off the beaten track, you will see many uninhabited and dilapidated houses, historic façades that no one has cared for since decades.
Oporto does not impress primarily with outstanding individual buildings or by its architectural layout, the pleasure is more to stroll through the narrow streets, to discover some remote corners and to enjoy the atmosphere. But of course, there are significant buildings. Oporto is full of churches, most of which are Baroque, lavishly adorned in gold and with the omnipresent blue azulejos, testimonies of the glory of bygone times when Portugal gained its wealth from the colonies.

My highlights in the core zone are:

• Cathedral Sé do Porto with its cloister, and the narrow alleys and stairs down to the Igreja de S. Lourenco
• Igreja de Santa Clara, a small baroque church with a plain façade, but richly decorated with gilded carvings made of precious wood from Brazil
• São Bento Train Station, decorated with azulejos from the beginning of the 20th century, best to visit in the evening when the train station is less crowded
• Palácio da Bolsa, in particular the Arab Room
• Igreja São Francisco, next to the Bolsa Palace, the interior decoration is almost entirely in gold, and do not miss the catacombs
• Ribeira neighborhood with its narrow houses, the facades with colorful tiles or in pastel colors, some newly renovated. The area is very popular with tourists, there are many restaurants and bars on the riverside, but you see also washing on the line on the upper floors, indicating that most of the houses are inhabited.

Oporto is a good spot to visit potential sites of the TWHS Álvaro Siza's Architecture Works. Many of his buildings are located in the outskirts of Oporto and in neighboring cities. But it is not yet specified in the T-list entry which buildings would be part of a nomination.

When visiting WHS like Oporto, I always look also for interesting non-WHS-related stuff. My add-ons are:

• Casa da Música, the modern concert hall by Rem Kohlhaas, I would recommend a guided tour to understand why the building looks like this
• Capela las Almas or Capela de Santa Catarina, a little gem, probably the most beautiful example of the blue azulejos that I saw on my trip to Portugal
• Port wine tasting at Vila Nova da Gaia, I had a guided tour with tasting at Graham's, but there are plenty of other cellars, a nice addition to the visit of the Alto Douro WHS.
• Pont de D. Maria Pia, a railway bridge by Gustave Eiffel, about one kilometre east of the Ponte D. Luis I, but not in the core zone of the WHS. There are plans for a serial nomination of iron arched bridges in Portugal, France, Italy, and Germany.

Oporto is also a good spot to look for souvenirs, there are some special stores, not just the usual souvenir shops. Three examples:

• Oliva & Co, near Bolsa Palace, I had a delicious tasting of olive oil from northern Portugal, and also the tea from olive leaves is worth a try
• A Pérola do Bolhão, a grocery store. For whatever reason, the Portuguese love canned fish in countless variations, and they love to pack the cans in colourful paper. You’ll find that everywhere in Portugal, but this is one of the most lovely stores.
• Casa das Rolhas, a cork shop, not the usual souvenir stuff, but items for daily use and the household, bottle corks in all sizes etc.

Finally, a warning: a local culinary specialty is Francesinha. It is a sandwich consisting of bread, ham, fat sausage and the like, covered with melted cheese and served in a thick, fat sauce. If that is not enough, you can get it with french fries and a fried egg. One of these covers the fat requirement of a small family for a week. If you are courageous you can try it, I did it, but gave up halfway.

In my opinion, Oporto is one of the best WHS in Portugal, it has enough to offer to entertain a visitor for a few days and is one of the best destinations in Europe for a weekend trip.