Filtering by: File Format video/mp4 Remove constraint File Format: video/mp4 Digital Collection Series 5: Films/Sound Recordings Remove constraint Digital Collection: Series 5: Films/Sound Recordings Resource Type moving image Remove constraint Resource Type: moving image Subject scientific expeditions Remove constraint Subject: scientific expeditions Time Period (Topic) 1920s (1920-1929) Remove constraint Time Period (Topic): 1920s (1920-1929)