Miradouro is the Portuguese word for viewpoint, and the Miradouro da Vitória is perhaps the best known of these in Porto. The view over the Ribeira from here is a great way to take in some of the main sights of the city; the Dom Luis bridge, the Se and Bishop's Palace all stand out above the patchwork of terracotta roofs below.
What makes the Miradouro da Vitória particularly appealing is the fact it is free. There are other great views of Porto, for example from the top of the vertiginously tall Clerigos Tower, or across the river from the terrace of the Mosteiro da Serra do Pilar in Vila Nova de Gaia. However, neither of these are free.
When you find the miradouro, on Rua da Bataria da Vitória, you may spot that the viewing platform is on private property. Don't be put off, there is a sign declaring tourists are welcome.