The natives from Asia crossed an ice bridge called Beringia around 10,000 years ago to migrate to uninhabited North America. They made the journey in search of food, a new climate, and a new life, as changing conditions in Asia made surviving there difficult. The ice age had formed the land bridge between the continents, allowing people to follow animal herds for resources. Their migration led to the initial population of the western hemisphere and establishment of civilizations and culture.