Currently held view is that there were several waves of migrations via Siberia ? Alaska, during relative warm periods. There was also a theory that the Clovis people of America, may have been descended from the similarly tooled Solutreans of south west France, but a recent study has thrown doubt on this idea. (Previously aired in the Science Thread.)
Was it this series or similar?
NGC ? The Human Family Tree
It may be part of that series, but the theory put forth is that humans traveled from all over the eastern world via boats into the Americas as well as the the Siberian land/ice bridge.