Before Portugal even existed there were people already living here. Obvious, right? Those people built huge stone monuments, some of which made their way to our day and age more or less intact.
Not much is known about them, but they’re thought to be approximately 5000 years old. You can find examples of this type of pre-historic monument all over the country, but mostly in the north and in Alentejo (as far as I know).
Truth be told, they’re not always easy to find, even when they’re mentioned in maps and hiking trails. Sometimes you’ll just have some obscure reference to a dolmen in a particular area and little more information besides that.
But who doesn’t love exploring around a bit? 😉