Giant Translucent Bat Wing

I've been in the studio all afternoon working on this 55" tall drawing; a drawing that tall was made by combining two pieces of paper. Lacking the space to work on it all at the same angle, I had to rotate it constantly, which is why there are two sides that could be facing upwards. I used spraypaint, gesso, NuPastel, and probably some other thing I'm forgetting at the moment. I kinda want to replace those buildings on the bottom half with something more interesting, but I don't know what.