Things to do with a non-useable fire places in bedrooms?

[Faithless]

We've just moved and have 2 fireplaces in the largest bedrooms. They are small and ok looking, just plain black tiled. I would like to keep them as they are, but put something nice in them and make a feature.
DP and my room fireplace currently has glass pebbles in it and girls' room (8 year old dsd stays 4 days every other week and 18 year old at uni, back in holidays) currently has logs in.
Colleagues suggested large glass vase with fairy lights for girls' room, which I like and I'm thinking candles for our room.
The house is 1930s with bay windows & original features (picture rails, ceiling with wooden trim thingys, stripped floors), so quite traditional, but I tend to like quite minimalist modern things. Both girls like girly things.
Any better suggestions?
Thank you

[blueteapot]

A selection of chunky white candles in storm vases of different sizes / holders? Not sure what I'd do in a kids room though, the fairy lights sound pretty?

[Qwebec]

here there is a few suggestions

offbeathome.com/2014/09/non-functional-fireplaces