"Nanook of the North (also known as Nanook of the North: A Story Of Life and Love In the Actual Arctic) is a 1922 American silent documentary film by Robert J. Flaherty, with elements of docudrama, at a time when separating films into documentary and drama did not yet exist."
"In the tradition of what would later be called salvage ethnography, Flaherty captured the struggles of the Inuk man named Nanook and his family in the Canadian Arctic. The film is considered the first feature-length documentary. Some have criticized Flaherty for staging several sequences, but the film is generally viewed as standing "alone in its stark regard for the courage and ingenuity of its heroes."
1 hour 18 minutes
Note: Given the current climatic condition of the Arctic, such a genuine film would not be possible in this day and age.