Human hands too, added their personal touch in a way that makes you feel the passing of age. Here and there the architectural designs resemble the fantasy of Art Deco. From tunnel entrances stare down carved gargoyles and winged beings that cling to your memory much longer than they should. Those grotesque gargoyles are dark and look like a preview of the Nightmare Hall. Some of the faces of the frightful creatures depicted have lost details in a way that softens the ugliness.
History has a way of erasing details and the memory of the original form.
Just as well, perhaps the gargoyles were carved from live models. The symbol that marks the portal is the symbol for marsh, or wet lands. After a few miles the rock tunnel walls became mostly white in color and were decorated with carved plant life of all kinds. Here, I saw ancient fern trees with huge Rose like flowers depicted in beautiful relief. These beautiful walls portray a dense archaic tropical thicket.