Otzi the Iceman is the proud owner of the world’s oldest tattoos.

About 5300 years old, and discovered in 1991, he sports 57 of them, consisting of parallel and intersecting lines. There’s been enormous speculation as to the purpose of his tats: that they denote social status, that they served a ritual purpose, identified a tribal affiliation, or that he just plain liked the way they looked. One of the most commonly accepted and compelling theories, however, is that their purpose was largely medicinal. Many of the tattoos are over arthritic joints, which suggests that the earliest tattoos were also a form of prehistoric acupuncture. Acupuncturists and archaeologists have noted that many of Otzi’s tattoos correspond almost perfectly with acupuncture points still used today.