In his series of paintings, Anthropométries (1960), the French conceptual artist Yves Klein directed nude female models to cover their bodies with ultramarine paint, his patented International Klein Blue, and then press themselves against gigantic, hanging sheets of white paper. As the title suggests, “the study of human body measurements on a comparative basis,” Klein used their figures like inked, human stamps to make imprints. The sight of erotic bodies, the smell of fresh paint wafting through the air, and the sound of materials, dripping paint and rustling wall paper, against bare skin, another material, mixed with Klein’s verbal instructions and classical music from a small orchestra, likely created a hypnotic, sensory experience for everyone present. It would have been especially striking for the captivated mid twentieth century audience who, like Klein, were dressed in conservative suits and bowties, dresses and pearls. During Marina Abramović’s Rhythm 4 (1974), the artist recorded herself naked in the stark, white cube of the Diagram Gallery in Milan, crouched on her knees for 45 minutes. An industrial fan violently blasted air into her lungs until she collapsed and passed out. The rhythmic breathing of her body was overcome by the powerful machine, captured in photographs that still shock viewers more than fifty years later.