Walk the Spiral
This was the water-filled tube in which the heroes found themselves upon awakening and escaping the cocoons of the dream catchers. It was, in fact, mostly filled with silt and fallen rock, but still had a narrow shaft through with they were able to reach the surface.
Despite its location on a lake shore, it came to be referred to as a well because of its superficial resemblance. The “zodiac” title came from the fact that symbols of the zodiac signs, including a 13th symbol somewhat reminiscent of a caduceus, were found carved around its circumference.