The idea was that massive spiders used to live here, eating anything that came into the valley. At some point, an army cleared what remained out. They established a city in the valley.
So, no immense spiders there now!
Glad you like it! I don't do many environments. This was really meant as a basic concept sketch. Apparently I did something right as it has received a lot of attention.
In any case, thanks so much for the comment. Hopefully my future pieces will garner even 1/4 of this kind of interest.