Officially the Adm. Byrd's mission was a geographical, biological and metereological one.
In
facts the U.S. Intelligence was really concerned about the Nazi
research of the secret Antarctic Doors, according to the "Hollow Earth"
theory. There were also rumours about a Nazi "Secret Disk-Shaped Planes
Factory and Military Air Base" in the area.
The possibility of the
passage of unknown weapons and Axis' troops through the Earth, able to
hit the USA by surprise from the underground, was taken in serious
consideration by the American Intelligence at the end of the 1930ies. To
control the Germans in their activities in "Neu-Schwabenland" was
considered a priority in the early times of WW2, at least before Pearl
Harbor's attack and the US involvement in the conflict.
In this
recently declassified original silent footage there's much more that
meets the eye than the trip to Antarctic and the daily life of the crew.
There are really revealing and unexpected shots here and there...