In late 19th-Century Poland, prison tattoos were cut from the bodies of deceased inmates and preserved to identify connections between convicts.

Today, those samples are art, and 60 of them have been captured in haunting and beautiful photographs by Katarzyna Mirczak. The photographer found them at the Department of Forensic Medicine at Jagiellonian University in Krakow, Poland and wanted to show how prisoners would use a variety of inventive -- but often dangerous -- materials to tattoo intricate designs in their skin.

It was forbidden for Polish prisoners to tattoo themselves, yet they'd use clips, pins, wires, razor blades and pieces of glass to puncture their skin and add any number of substances to make the designs permanent, according to a Mirczak press release. Colors were formed using powdered charcoal, burned rubber, cork, pencil refills, ink, watercolor and crayons. Those pigments would then be mixed with water, urine, soap, cream or fat.

Some of Mirczak's photos are featured below. Some tattoos -- preserved in formalin with the flesh still intact -- are biblical in nature, while others are sexual or represent a prisoner's vow to get revenge. All of them meant something.

Mirczak included a key to the symbolism:

Devil's head - symbol of cruelty and a prisoner who takes action to spite of others.

Flying eagle - an emblem of a prison in Wroclaw, Poland.

A dagger with a snake twisted around - the oath of revenge - is a sign of planned assassination.

A snake twisted around a woman - a sign of revenge on an unfaithful woman, who betrayed or snitched on somebody; it's a symbol of planned revenge, not yet accomplished.

A sailor silhouette - symbol of a person who worked with goods and foreign currency trading; popular in the People's Republic of Poland.

Half-moon with a woman sitting on it - symbol of a person who is interested in act of cunnilingus.

Mouth - usually open and red - identifies a homosexual.