I arrived in Porto with a list, and I got through most of it. What I hadn’t planned for was how much of the city I’d see just walking from one thing on the list to the next.

Porto is compact enough that you rarely need anything more than your own feet, and steep enough that you’ll make frequent stops, meaning you’ll discover plenty that’s not on your itinerary. For a short break, Porto is close to perfect. You can get to know it in three or four days (but add an extra day if you plan to explore the Douro valley) and still leave with the sense that you would quite like to go back.

If you only do one thing, get on the river. We took one of the commercial cruises from Cais da Ribeira, which takes you under the city’s six bridges in about 50 minutes. From the water, the city takes shape and makes sense. You see the tiled houses stacked up the hillside and the port lodges lined along the opposite Gaia bank. Next time I’d consider hiring a boat for half a day instead, though. It looks well worth it because you can go at your own pace, pause for photos and follow the river all the way out to sea.

Porto is a very, very photogenic city, and not only for its tiles and rooftops. I’ve never paid much attention to bridges, but in Porto you can’t miss them, and they are impressive. Gustave Eiffel’s former partner, Théophile Seyrig, designed the Dom Luís I, which opened in 1886. Eiffel himself built the Maria Pia bridge in 1877. When you’re back on dry land, walk across the upper deck of the Dom Luís I for the fantastic view back over Ribeira.

I was told more than once that Porto has never been conquered. It isn’t quite true, as Napoleon’s army occupied the city in 1809. But the later nickname Cidade Invicta is well deserved. During Portugal’s civil war in the 1830s, Porto held out through a siege that lasted a year and a half and never gave in.

Much of Porto’s beauty comes from its tiles, and you’ll see them everywhere in the old town. São Bento station is worth a visit even if you’re not catching a train. Its entrance hall is lined with thousands of blue and white azulejos that tell the story of Portugal.

The Church of Saint Ildefonso has its tiles on the outside, and it’s great for photos – particularly in the late afternoon light. The Palácio da Bolsa is the old stock exchange, and it is grand and serious, with rooms in various design styles. The guided tour ends in the spectacular Arab Room with intricately gilded plasterwork, the most beautiful wood marquetry, all topped off with 18kg of gold leaf. 

For a great viewpoint, climb up Torre dos Clérigos, but be warned it’s a hell of a climb up this 75-metre tower. Best to do this on your first day, when your legs are still fresh, and you’ll get your bearings for the rest of your visit. In the evenings, the church below presents Spiritus, a half-hour show of light, colour and music that lights up the baroque interior. It was loosely inspired by Álvaro de Campos’s poem ‘After all, the best way to travel is to feel’. I thought about that line for the rest of the trip.

Livraria Lello is often called the most beautiful bookshop in the world. You can understand why once you’re standing at the top of its curving red staircase. J.K. Rowling lived in Porto in the early 1990s while teaching English and working on the first Harry Potter book.

For years the shop was said to have inspired Hogwarts, but Rowling has since said she never actually went inside. Nobody queuing outside seems to mind. Buy a timed ticket online and go early. The entry fee can be put towards a book, which is a lovely touch and mitigates the feeling that you had to pay to see a bookshop.

I found the people of Porto really helpful, and it didn’t feel put on. I never once got the feeling that locals would prefer not to have you there, which is something I’ve become very understanding and sensitive to over the past few years. Many of the city’s artists sell their own work from small studios, shops, and market stalls. It’s worth making the effort to find them. There’s plenty of tourist tat about, but if you look beyond it, you’ll find some lovely things to take home.

Porto is very touristy, and the Ribeira waterfront and the streets around Lello can feel like a queue. The good news is that it doesn’t take much to escape; you can quite easily get off the beaten path by walking along the river to Miragaia. It’s one of the city’s oldest quarters and has the same narrow medieval lanes and brightly painted houses as Ribeira, but without the crowds.

Or take the regional train south from São Bento to Miramar or Aguda. In barely half an hour you’re by the Atlantic in quiet seaside suburbs where the small chapel of Senhor da Pedra sits on the rocks at the water’s edge.

And for port, skip the big-name lodges in Gaia and book a tasting at a smaller independent house such as Poças. It has been a family business since 1918. You’ll sit with a handful of people rather than a coachload, and you’re far more likely to have an authentic experience.

To me, four days were enough to fall for Porto but not enough to be done with it. The Douro Valley and a half-day on that boat are both on the list for next time. And there will be a next time.