The Petrified Forest National Park in Arizona is so named for its unique and plentiful petrified wood, formed from conifer trees that lived there some 225 million years ago. As more than 500,000 people visit the park each year, inevitably, not all heed the US National Park Service’s guidance to ‘take only photographs, leave only footprints’. And, as the acclaimed short documentary The Conscience Files explores, a small but not insignificant number of visitors come to deeply regret their decision, taking it upon themselves to return the stolen rocks via mail, and provide a written explanation. Some even come to believe a long-circulating rumour about the park: those who steal rocks from the land are cursed.

For the film, the US director Brian Bolster was given access to the park’s archive of these letters, which blame the ‘curse’ for everything from the deaths of loved ones to the outbreak of a family stomach bug. Some are lighthearted and others are tragic. However, what most share is the need to unburden a guilty conscience and a desire to assign cause and meaning to the bad things that life seems to arbitrarily dole out. Pairing readings of these letters with scenic views of the park, what emerges is a rich, panoramic portrait of both the place and humanity itself.