Brides of the wind

Wow - this is amazing!

I love the "ghostly tone" of this picture, and how it looks quite greyscale yet if you take a second look you see all the blue tones. What I really love is all the detail! And how this picture looks "full" on the one hand, with many many elements, yet still organized and not chaotic. And I like the visible pencil structure

May I ask - how large is this drawing in original?