Underworld Gate - Gustave Doré/Paradise Lost Inspired

I was inspired by an engraving by Gustave Doré in a Paradise Lost book I found at a used book store. I always thought some of the shapes and details in his work would transfer really well to 3D. In the end I don't think it is totally accurate to the illustration or the description in the book but that is ok, it is still heavily inspired by it while having my own interpretations. Thanks to everyone who provided me with great feedback and technical help.