With the Neolithic the first great revolution of mankind, there will be big changes and they appear also the first monumental architecture of Galicia, the Megalithic, which mainly take place in the 3rd millennium B.C.

It is the architecture of the "menhires", the "dólmenes" and Cromlech ".

Important in our concello have dolmens or tumuli, of which we have numerous samples. The mámoas had a funerary function, although some authors point to other possible functions (social, religious, territorial marks etc.).

Its location is semper conditioned by a number of factors: proximity of the quarries, suitable land so they could be spotted from afar etc. The mámoas Morrazo were excavated mostly in an archaeological campaign led by Ramón Sobrino Lorenzo-Ruza, despite the espolios suffered previously attracted much attention the amount of remains found, compounds funeral votive offerings by: machados polished fragments ceramics, arrowheads, microlitos, etc.

Many of these findings, from the megalithic necropolis of Chan de Armada, Arquiña Chan and Chan Castiñeiras, ranging between concellos Marin, Vilaboa and Moaña, are now in the archaeological room of the Museum of Pontevedra. In Marin we mámoas in Monte Campolongo (Pastoriza, Ardan), Forno de Arcas (Pastoriza), Chan da Armada (San Tomé de Piñeiro), Lagucheiros (Pineiro), Allariz-Pedra da Mina (Pineiro), Gagan (Pineiro), Pedralonga (Lake Castiñeiras), Outeiro (San Xulián) and Campo dos Mouros (Mogor).

Megalithic also have Pedrafita known as Casa Vellas ou Currás, menhir of 3.14 m. high by 9'5 Tm. of weight. It presents some engravings, mainly bowls, and in 2003 lost its original site because of the construction of the ring road of Marin. According to researcher J. Alberto Alonso Fernández, this Pedrafita of Currás would be an astronomical observatory Neolithic.