Figure above:

Engraved slab belonging to the megalithic burial monument of Newgrange (Ireland), dating back to about 3,200 B.C. The spiral decoration with wavy lines is rather usual in megalithic art and has been interpreted by Marija Gimbutas as representing the generative force of a female goddess (Gimbutas 2005b).
[Image: http://goeurope.about.com/od/ireland/ig/Newgrange-Pictures/Newgrange-entrance-stone.htm]

Figure below :

Overview of the monument of Newgrange (Ireland), showing its great dimensions. It is likely that this kind of buildings had the function of ceremonial places, where not only funerals, but also communal rituals were performed at special times in the year. The oval mound covering the sanctuary-tomb is sprinkled with white quartz and it seems a huge egg-shaped dome. According to Marija Gimbutas (2005b: p. 5823) “it meant to represent a gigantic cosmic egg, the womb of the world”.
[Image: http://www.ouririshheritage.org/page_id__62_path__0p2p.aspx]