In the vast period of time known as the Palaeolithic or Old Stone Age the forbears of modern humans developed stone tools and lived a nomadic life following the animals they hunted whilst also gathering food from plants. The oldest evidence of human activity in Wales dates to about 220,000BC when Neanderthals lived in Pontnewydd Cave in modern Denbighshire. Very little evidence of human life in this period survives, largely due to later rises in sea levels submerging the coastal areas and grasslands favoured by people at this time. Modern humans had emerged by the end of the Palaeolithic.