44000 BC: Eruption of the Traiter volcano and release of the large basaltic lava emission on which the town of Les Planes rests.

27000 BC: Eruption of the volcano Artigues Roges or Puig de Sant Marc, upstream of Les Planes.

7000 BC: Epipaleolithic hunters lived in caverns, in the Clot de l'Infern (les Encies)

4000 BC: Neolithic farmers lived in the Cogolls valley and were buried in the Avellaner cave.