You could use it to display pictures, photographs, artwork, depending on which part is along which room. The entryway could have a large mirror, the schoolroom part could have artwork created by kids which could be clipped on some jute string with clothes pins, making it easy to change around; the living room could have a combination of artwork/mirrors formal photographs, the kitchen could have more kitchen-related items about food, perhaps. The entire wall could be a gallery wall, unified in purpose but broken up by theme/subject. Group them accordingly. It should be something to build on over time, room to grow. When you say you cannot place anything against it I am assuming you mean furniture-wise. Remember, you do not have to fill up the entire wall space but it is a perfect area to have meaningful pics on display.
It is the best I can recommend without a pic of the wall. You could send me one if you like.
I am an Interior Decorator. My blog is A Room with A View, http://www.lminteriorsllc.blogspot.com . Check out the wall decals, another thing to consider - decorative and for displaying photographs. Hope this helps. You can always contact me if you need any further suggestions.