I guard the coast but never march. I wear a spiral but have no shell. I flash my eye but cannot see. What am I?

I am a path that doesn't touch the ground. I stretch across the widest rivers and span the deepest valleys, yet I never move an inch.

I stretch far and straight from town to town, with steel on wood where wheels roll down. I carry people, cargo, too, what am I that runs straight through?

I am carved by patience, not by hands, A wound in the earth that time expands. Walls of crimson, amber, and rust, Born from water reducing stone to dust. What am I?

I rise high into the sky, but I am not a mountain. I sometimes hold bells or water. I even have a spiral staircase and offer a view from my top.