The corridors of the cave that led to the Oracle were built with a narrow trapezoidal shape since being inside a mountain the weight of the earth and rocks that had over it was huge so it was necessary to have stability and resistance for it to be safe to enter and leave at all times, the only exception was the entrance of the private room of the Sibyl which is made of a flattened arch form which was impossible to be done at that time because they did not know such structures and constructions , not to mention that the bow appears to be carved into a single piece of stone and not several blocks as they used to carve, which makes it even more bizarre and intriguing.

Den della Sibilla

CONSTRUCTIVE TECHNIQUE