LONG BEFORE the white man set foot on American soil, the American Indians, or rather the Native Americans, had been living in America. When the Europeans came here, there were probably about 10 million Indians populating America north of present-day Mexico. And they had been living in America for quite some time. It is believed that the first Native Americans arrived during the last ice-age, approximately 20,000 - 30,000 years ago through a land-bridge across the Bering Sound, from northeastern Siberia into Alaska. The oldest documented Indian cultures in North America are Sandia (15000 BC), Clovis (12000 BC) and Folsom (8000 BC)