The earliest confirmed inhabitants of Ireland were Mesolithic hunter-gatherers who arrived some time after 8000 BCE, when the climate had become more hospitable following the retreat of the polar icecaps (although remains thought to be from before 9000 BCE have been found at Kilgreany Cave in Munster).[4] While some authors take the view that a land bridge connecting Ireland to Great Britain still existed at that time,[5] more recent studies indicate that Ireland was separated from Britain by c. 14,000 BC, when the climate was still cold and local ice caps persisted in parts of the country.[6] The people remained hunter-gatherers until about 6000 BCE. It is argued this is when the world's first signs of complex agriculture started to show with the discovery of the Céide Fields in Connacht, leading to the establishment of a high Neolithic culture, characterised by the appearance of pottery, polished stone tools, rectangular wooden houses and communal megalithic tombs.