Portugal is a lot more mountainous than most people think - especially in the whole of the country's North East the terrain is mostly alpine. This region is often referred to as simply "the Mountains" within the tourist industry, although this is not an administrative unit. The highest point within mainland Portugal is the so-called Torre ("tower"), which rises 1,993 meters above sea level, without technically being - a mountain! Rather, it is part of an extensive plateau and mountain range, the legendary Serra da Estrela. You can actually reach the Torre by car on paved road - and then you will find an upscale restaurant, gift shops and the famous Vodafone Ski Resort.
Further North, not far from the Spanish border, one can visit the popular tourist destination Mirandela, which is just a little town with a lot of history.
Don't expect large cities in the Portuguese mountains! They haven't been built. Many of the towns are older than two millennia, but they have never really grown into cities - those you won't find. Instead, there are small towns and then village after village, all with their very distinctive culture - and culinary features.
Take Viseu as another example. This lovely mountain town was founded by the Romans as "Viso" - meaning "good view" (most Portuguese place names either go back to the Romans or to the Arabs). It's a renowned center of viticulture, to be exact of Dão Wine, which is grown in and around Viseu. But recently, the town has also turned into of the major hubs for telecommunication and IT within the country, and that with a population of less than 50 thousand. That's Portugal...