Ceide Fields is a field system and settlements site dating to 3000BC and before. It is the most extensive Stone Age monument in the world with dwelling houses, tombs and stone walled field systems. There is a visitor centre on site which is open from late April until late October and which is about eight kilometres west of Ballycastle (Irish: Baile an Chaisil) on the R314 in the north of County Mayo, Ireland (Irish: Contae Mhaigh Eo, Éire). This is an extremely important archaeological site.
The importance of Céide Fields originally began in the 1930s. Schoolteacher, Patrick Caulfield, noticed the formation of rocks as he was cutting peat for fuel. He saw that the configuration was clearly unnatural and deliberate. Because the rocks were positioned below the bog, they had to have been there before the bog developed, implying a very ancient origin. Some forty years later Patrick Caulfield's son, Seamus, who had studied archaeology, undertook further work on the site. His investigations revealed a complex of fields, houses and megalithic tombs concealed by the growth of blanket bogs over the course of many centuries.
Link: Ceide Fields website
Image: Ceide Fields Neolithic site courstesy of wikipedia.