How did humans spread across the Earth?
A narrow sea channel known as the Bering Strait divides Asia from North America. During the last Ice Age, the sea level was lower than it is today and the two continents were connected by dry land. Prehistoric people from Asia crossed this land bridge and spread down into the Americas, becoming the first Native Americans. Then, around 10 000 years ago, the sea flooded the Bering Strait and left the Indians stranded. It is though that the first Aborigines reached Australia from South-east Asia in prehistoric times. New Zealand and other Pacific islands were settled by seafaring Polynesian islanders in more recent times.