For today's visitors, it is not immediately apparent that Guimarães played such a significant role in Portuguese history, it is closely related to the foundation of the Portugal and is often referred to as the "cradle of the nation". The Castelo de Guimarães is said to be the birthplace of the first king of Portugal, Alfonso Henriques. Thus it's a good idea to refresh your knowledge about the origins of the Portuguese nation prior to the visit. If not, you can learn the most important facts in the small exhibition at the Castelo. They show also a copy of the Manifestis Probatum, the papal bull in which Pope Alexander III recognized the Portuguese king and confirmed the independence of Portugal from the Kingdom of Castile.

The castle looks just like one imagines a medieval castle: a central keep surrounded by a ring of high walls and eight crenellated towers. You can walk on top of the wall around the entire castle, the photo shows the view to the two other buildings in the small park, the Paço dos Duques de Bragança and the Igreja de São Miguel.
The Bragança Palace was built in the 15th century and was for several decades the residence of the Dukes of Bragança until they moved to Vila Viçosa. The Palace has a quadrangular plan and is built strictly symmetrical around a large courtyard, most striking are the high brick chimneys and the sloping roofs. The interior is rather austere and simple. Parts of the building house a musuem with historic furniture and decorative arts, not really exciting, remarkable are the large tapestries.
The role in Portuguese history is only one criterion why Guimarães was inscribed on the WH list. Other criteria were that it is "an exceptionally well preserved town, (that) illustrates the evolution of particular building types from the medieval settlement to the present-day city" and that "specialized building techniques developed there in the Middle Ages (and) were transmitted to Portuguese colonies" (cited from the Unesco website). And these are exactly the aspects that make the special charm of this WHS.
After having visited the palace and the castle, I strolled through the narrow streets of the historic centre, enjoying the city and its atmosphere. I liked that it was not overcrowded with tourists, it's a lively small town, souvenir shops for tourists and normal stores for the locals side by side. The town centre has preserved a harmonious architecture and design: small, old houses, arches spanning the narrow streets, most of the houses with wooden balconies or wrought iron balustrades. This can best be admired in the Rua de Santa Maria and the central square, the Praca de Sao Tiago. The most striking individual buildings in the core zone are the Igreja de Nossa Senhora da Oliveira, the former Convento de Santa Clara (today the Pálacio de Justiça), and the remains of the city wall along the Av. Alberto Sampaio.

I spent half a day and an evening in Guimarães, I stayed there overnight. That's enough time to properly visit this WHS. Guimarães can also be easily visited as a day trip from Oporto, if you are traveling by car it can be combined with a visit to the TWHS Bom Jesus de Monte in Braga.