Poland’s Jagiellonian University has some pretty interesting research collections. And one of them includes a jaw-dropping collection of prison tattoos preserved in formaldehyde. It’s not there so much for shock value as it’s there for a look into the past. ‘Tattoos back then were markedly different than their modern counterparts,’ where they used a method called ‘stick-and-poke’. Instead of needles, prisoners used to be ‘equipped’ with tools such as razor blades, broken glass, paper clips, or even wires. And ‘ink was substituted for pencil refills, charcoal, watercolor paints, or crayons mixed with water, fat or urine’.