The Hermit (Anthony Dean Wells)

The Hermit (Anthony Dean Wells), a member of Ken Kesey’s Merry Pranksters, during the group’s LSD-fueled Acid Test Graduation party in San Francisco, 1966. Like Davy and the Romantics more than a century before, 1960s counterculture experimenters sought intellectual and spiritual enlightenment through hallucinogens.

Ted Streshinsky/Corbis/Corbis via Getty Images