There are archaeological traces of mankind in Brittany which date back to 700 000 years BC. We know very little about the population which, during the Neolithic period (5500 to 2000 BC), made Brittany the centre of megalithic civilisation. Other than various tools which bear witness to advanced development, the remains of this period are more intriguing than comprehensible. They include menhirs, which are often isolated (such as at le Champ-Dolent, near Dol-de-Bretagne), or grouped into lines (Carnac) or Cromlechs (stone circles), or Dolmens (at Locmariaquer), covered alleys (La Roche aux Fées in Essé) or even Cairns (such as in Bamanez in Plouezoch, near Morlaix) or Tumulus (Gavrinis in the Gulf of Morbihan, Bourbriac).