That river in Egypt

"This is Pandemonium, painted by John Martin in 1841. In John Milton's poem Paradise Lost, Pandemonium is like the capital city of hell, where Satan and his buddies live. It's not as insane and imaginative as the other depictions of hell I have saved here, but I like the enormity of the building. Of course the capital of hell is big and evil. I wonder what the demons even do in there, what use do they have for such a large building, paperwork and accounting?"

https://commons.wikimedia.org/wiki/File:John_Martin_Le_Pandemonium_Louvre.JPG