It's like a transom that isn't matched with a door or window. When my parents built their house they deliberately left spaces like this between several rooms and glassed them in from both sides. They can be opened (I think some of the glass slides), and they display some of their glassware etc up there, but thanks to the glass there is no dust problem. Buying some tracks for sliding glass panels and installing them yourself might not be rocket science. Even easier might be to install something fixed. You would simply get long pieces of wood, maybe 1x2s (thinner might split when you nail or screw it), and attach strips of it off-centre on the ledge itself, up the sides of the opening, and across the top. Then put a panel of plywood, glass, or plexiglass against that frame, and install a similar set of strips against that panel to hold it in. You cold get as fancy as you wanted with painting or wallpapering the plywood, using coloured or stained/leaded glass, or what have you with plexiglass. Heck, it could be a piece of artwork. You could change it out from time to time. You'd still get dust on the ledge a bit, but one of those long-handled dusters would take care of that. I also like Dilly's suggestion of hanging a panel inside the opening or across it. You could actually just treat it like a window and explore various drapery-type options such as a valance or a high curtain even - a curtain from both sides would keep the dust out. Sheers would still let light through. All you would need to install would be a rod on each side. It all depends on whether you want the light coming through and whether you care if sound etc is transmitted (good point on that one, Dilly!). KarinL

I'm guessing the top right corner is an optical illusion and not moulding that's not attached. I think that piece is actually trim on the perpendicular wall. Same for the two pieces where the stairs turn. Looks like they used a wide board where the balusters attach at the bottom to beef it up. As for the skirting missing on the left, it's also missing on the right. That's a builder cutting corners, not a design choice. I have the same on my stairs to my unfinished basement. Stairs are carpeted wall to wall with no skirting. Doesn't bother me since it's the basement, but for this, your sheetrock walls are going to get dinged up.

Sorry I didn't post the other areas....here they are. The hutch/china cabinet were separated for the move. I looked and looked for a tv credenza but didn't find any I thought would go. Then I saw on Pinterest how people took old china cabinet tops and put them on legs so did this until I find a credenza I like. We bought this set in 1981 when we got married...it is solid and better made than what I could buy today so decided to keep it. We redid the handles...it originally had teeny gold handles. Oh, sorry for junk on DR table....am about to make chair covers. LR furniture/art/rug will be replaced in a few years....not crazy about the charcoal sofa/chairs anymore but living with it for now. Thanks for all the suggestions.

Is that going to be sturdy enough to use as a footstool, or it is purely decorative? I would leave as is because you will have to fill in the entire shape, including the face if you fill in the rest. But, if you do fill in the skirt, it looks like the same texture stitch you used for the shoes would be an idea to consider using. Is that grey patch on the chin to be chin hairs or just the hair wrapping around the head? I am going with chin hairs. That could use a bit more subtle stitching, maybe something wiry. I understand that poem now that I am of that age.