In Bad Luck, Hot Rocks: Conscience Letters and Photographs from the Petrified Forest, Ryan Thompson and Phil Orr document everything in the national park's "conscience pile" — the name park employees give the mound of rocks that have been returned by guilty thieves. While some people just felt bad, others became convinced they'd been cursed by taking the petrified wood out of the park.
The conscience pile exists because the rocks can't just be returned to random places in the park — that would contaminate the scientific research of the area. While warnings of fines and vehicle inspections are erected in the park, a display in the visitor center featured a few letters warning of cursed luck for any thief. Thompson and Orr became interested in the letters, and discovered that there were actually 1,200 letters going back to 1934. They are incredible artifacts of people both attributing bad luck to their bad action and seeking to end a curse and those who just couldn't let go of the guilt.