The Basque population is distinguished physically by a high incidence of Rh Negative factor in the blood. No one knows exactly where the Basques came from. Some say they have lived in that area since Cro-Magnon man first roamed Europe. Estimates of how long they have lived there vary from 10,000 to 75,000 years. Some say they are descended from the original Iberians.
More fanciful theories exist, as well.
One is that the Basques are the descendents of the survivors of Atlantis. Just as no one is sure about the origins of the Basques themselves, linguists are not in agreement over the origins of Euskara, the Basque language, either. That is, it is not related to any other language in the world. Since most of the Basque speakers of the world live in that area, these numbers give us a close estimate of the number worldwide. There are also pockets of Basque speakers in Latin America and in North America.