This is the first temple. a dark grotto completely hidden by the vegetation, completely obscured by small waterfalls.
One had to dare to pass, dare to go through the water to discover the god.
The god is Pan. This Pan was an extraordinary automaton. It was destroyed in 1712.
In the grotto's night and darkness, Pan represented the chtonic, underground, brutal and blind forces.
You would be correct in expecting the other temple to represent the favorable,
luminous and orderly forces of day.
Indeed, in contrast to Pan's wild grotto, here, at the other end of the perspective, is a more perfected, more civilized temple.
This temple was built to look as though it had been hewn from the rock. It shelters a statue which has survived -- Diana.
A Diana who causes the water of Knowledge to spurt out by squeezing her breasts.
This is the lesson of the bishop princes of BAGNAIA.