Answer:

1. The Ceide Fields in the north of County Mayo, on the west coast. It is the largest known stone age enclosed site in the world. People lived for a number of centuries on 1,200 hectares of farmland which they had enclosed with stone walls to keep their animals in; co-operation is implicit from the form of agriculture practised. There is no evidence of fortification or defences, and homes were scattered (remarkably similar to land occupation patterns today). Some of the walls have been excavated from the blanket bog which covered it and which also preserved the stone remains in their original form.