I missed the seguey - what does a creepy park have to do with masonry?
You wrote of secret rituals in a cave . . .
I provided a likely location.
Untermeyer Park is where David Berkowitz (Son of Sam) went with his group to worship Satan. Dead dogs, with their ears carefully excised, were found. There is a Hispanic presence in the area today and evidence of Santeria ritual sacrifices are found in woods now.
Just having a little fun . . .