Who were the first people to populate the Americas, and when did they get here? A few years ago most experts would have agreed that the first Americans walked across the Bering land bridge from Asia, about 12,000 years ago during the last ice age, then found their way south through an ice-free corridor, and went on to populate north, central and south America, hunting big game as they went. This theory -- called the Clovis-first theory, named for the site in New Mexico where these people's finely worked stone tools were first uncovered -- has now been called into question. Depending on who you ask, people came from Asia, or Europe, or the south Pacific; they walked or they came by boat; and they came in different waves, with some surviving, some dying out. A wide variety of evidence, from linguistics to DNA analysis and climatology, is now being called upon to contribute to this newly-enlivened field. This program will sift through it all, and attempt to figure out who the first Americans were.