In what is now Galicia, during the Neolithic period, that is to say, between 4,500 and 2,500 BC, the construction of thousands of tumuli, that is, burial mounds of earth and Stone that host different types of constructions -the most well-known being, dolmens or megalithic chambers- which are intended to house collective burials.
The burial mounds are the first examples of monumental architecture documented in Europe and one of the oldest in the world, since nothing similar has been found in the previous 4 million years of evolution of the human race.
The tumuli, or burial mounds are a monumental human creation characterized by:
1- They are an artificial creation that involves the mobilization of the effort of many people for a funerary purpose.
2.- They were built to be visible across the landscape and to be everlasting. The appearance of these structures tells us of the profound social and cultural change experienced by Neolithic people, who inaugurated new social conditions and ways of understanding the human relationship with the land, creating an artificial monumental passage that consciously and deliberately transforms the landscape.
These burials are not the only cultural (architectural or artistic) manifestations of the Neolithic period, as alongside them we have to include the menhirs (single standing stones), the cromlech (lithic circles such as Stonehenge), or the alignments of megaliths (such as that of Carnac, in French Brittany).
The society that built these types of funerary monuments had a mixed economic base, which revolved around the hunting of animals, the gathering of fruits and, for the first time in the history of mankind, the domestication of animals (the dog, the pig, the sheep ...) and the cultivation of cereals and vegetables.