We head up the Aldan River; for Bill Fitzhugh, it was a first. A tributary of the Lena, this river has provided a framework for the study of Eastern Siberia's prehistory; some archaeologists believe that traces of the earliest Inuit cultures can be found along its banks. Bill explained to us that sites along the riverbanks give evidence that Yakutia may have been settled as much as 30,000 years ago.

It's an exhilarating flight. Harnessed in with climbing rope, Marc photographs from the An-2's open door. The landscape changes from that of a floodplain valley to a river channel, and the tributary's waters run clear, free of the clay deposits that characterize rivers of glacial origin.

Copyright © 1995 Discovery Communications, Inc. Photo: Marc Bryan-Brown