The earliest evidence of humans in Ostrobothnia is at the 120,000-year-old settlement near Kristinestad, the only known indication of the pre-ice age presence of Neanderthal man in Fennoscandia. Modern humans arrived 9,000 years ago, as soon as the ice sheet disappeared and enough land had risen above sea level. A complex hunter-gatherer society emerged along the coast. Among the visible remains from this time are the Neolithic stone enclosures unique to Ostrobothnia known locally as Giant's Churches (). They are a rare example of monumental architecture built by hunter-gatherers in northern Europe.