Neolithic Revolution as irrigation and deforestation which allowed the production of surplus food. Other developments found very widely are the domestication of animals, pottery, polished stone tools, and rectangular houses. These developments, sometimes called the Neolithic package, provided the basis for centralized administrations and political structures, hierarchical ideologies, depersonalized systems of knowledge (e.g. writing), densely populated settlements, specialization and division of labour, more trade, the development of non-portable art and architecture, and property ownership. The earliest known civilization developed in Sumer in southern Mesopotamia (); its emergence also heralded the beginning of the Bronze Age. The relationship of the above-mentioned Neolithic characteristics
Neolithic and Bronze Age rock art in the British Isles might have been induced by the use of hallucinogenic drugs, evidence for which exists from Neolithic and Bronze Age Europe. This idea was first applied to the petroglyphs on the Neolithic monuments of the British Isles by David Lewis-Williams and T. Dowson. They noted that the depiction of phosphenes could appear independently in different areas due their common basis in the human nervous system. Lewis-Williams and David Pearce expanded on this idea in their book "Inside the Neolithic Mind". Bradley extended these ideas to suggest that the circular designs on open air petroglyphs might have represented a pathway that led