Mystery Photo 57 Revealed: Safe Storage
The colorful object shown in Mystery Photo 56 is a parfleche. Parfleches were made by Native American tribes out of rawhide and used as a suitcase of sorts or to store clothing or food.
Parfleches were brightly decorated, as is obvious from this photo. In Hidatsa and Mandan earthlodges parfleches were suspended from the ceilings to keep them out of reach and out of the way.
Rawhide discs were placed halfway up the rope to keep rodents "from climbing into the parfleche and provided protection from water damage in the event of a leak in the roof," according to the staff at Knife River Indian Villages National Historic Site in North Dakota.
While we had one correct answer (kinda), it was from Mike Jensen, who works for the state of North Dakota tourism department and who toured me through the state's National Park System units, including Knife River, and was there when I took the photo. Sooooo, we'll have to toss out his answer and congratulate those who guessed.