"The Creation of Adam" by Michelangelo (1512)
The artist's intent: God reaching out from heaven to create Adam in Eden.
The outcome: A human brain. No seriously, check out the shape of the cloth behind God. The borders da Vinci painted into it actually correlate to various parts of the cerebrum, the brain stem, the frontal lobe, the tiny pituitary gland, and more. Michelangelo was obsessed with human anatomy, so this metaphor was likely not accidental. However, the most eerily futuristic part of this painting is the crestfallen angel under God's arm, who is actually located in the part of the brain often activated on PET scans when a patient experiences sadness. How did Michelangelo know this in an age without brain imaging? Obviously, because he was some kind of god-man himself.