This nebula is one of the biggest in the Milky Way - I imagine aliens taking a peek from the Andromeda galaxy chittering excitedly as they view it through their own 'scopes - and is forming countless stars at its heart. Four of these, called the Trapezium, are so massive and hot their radiation lights up the entire cloud of gas.
But what you're seeing here is not just gas floating in space. This is actually part of a much larger dark cloud of dense material that you can't see, stretching well beyond the borders of this image. Stars like the Trapezium formed in this denser stuff, and once they switched on their intense radiation started eating away at the surrounding material. They carved a vast bubble in the cloud, which burst out through one wall of the cloud, more or less in our direction. Inside the cavity is much thinner gas, heated and glowing from the stars' ultraviolet light.
That's what you're seeing: the ethereal mist filling a burst bubble. The tenuous gas flows in ribbons, sheets, and filaments, forming those incredibly intricate wisps, and all of this sits inside a concave hole scooped out of one side of a larger complex. It's fantastic.
I can't imagine leaving you with a better picture than this. Or maybe I can, since I can point you to a much larger 4000 x 3800 pixel version. But even that might not be enough, so why not take a look at the huge 9000 x 8600 pixel (TIF) version? It's 142 Mb, but it may be the only true way to explore the profound beauty of this amazing galactic treasure.