Can you take a photo from farther back? I have no sense of proportion (like how high the ledge is from the floor, or how close the top of the arch is to the ceiling.

Without context, my inital thought was to let the windows be the star and not put any decor items there. I can't imagine what would enhance the area rather than take away.

Thanks!

Some idea

Wonderful! Thanks so much!!
I would love to add some greens/ flowers.. where can we accommodate that?

You could assemble a vignette in the niche using picture easels to hold up framed prints.

Here's now someone else addressed the windows over the fireplace.

I would put simple linen curtains hung inside the window frames with a top and bottom rod. Those glass block windows do not look attractive to me.

I would get one big spilling plant and put it in a large round bowl. Maybe a pair of candle sticks and a few tiny framed photos.

@Beverly- lovely! Thanks you the amazing idea and help with the products

Kendra’s- thank you! I thought about the curtains too but then you can see the top arc of the window

Some option with greens

If it were mine, I would paint the walls of the space a darker color, maybe that of the window frames or a color from the stone around the fireplace. Then use just a few low decorative elements as others have suggested. If it goes with the style of the house, you might improve the look by putting muttins in the central window. Or replacing the glass block with windows to compliment whatever you might add to the central window.

Another suggestion would be using a window film. They come in so many patterns, some busy and some mimic and mirror.

Static Flowers Blossom Home Decor Privacy Window Films Cling Stickers, 35"x98" · More Info

Dogwood Window Premium Film · More Info

Peacock Door Premium Film · More Info

One Way Mirror Film With Nightvision 5%, Charcoal, 36"x7' · More Info

Thank you Celery, njmomma,Yvonne! Such interesting ideas! We never thought of these.
In a way you can say that I am obsessed over decorating this particular space but no idea was appealing to me.
I am gonna try the curtain and window film and see how it looks. But I am more inclined towards using decorative pieces.

Please post an updated picture, I would love to see how you ended up decorating the fireplace.

For sure! It will take some time but sure will do!
Thanks everyone!