Oh my goodness, you have to check these out, and be sure to scroll down the page. Here's a couple as an example:
...and this is what they look like with the light off:
I really can't believe these are just layers of water-colour paper cut out with a light behind them!
There's a video showing the artists making one of these here.
I think I like 'A Drop in the Ocean' and 'Where The Giants Roam' the best...
These, by another artist, are gorgeous too.
...and another amazing artist who works three dimensionally with paper...