Full title: The image from 1987 shows an exhausted but vigilant Dr. Religa monitoring his patient’s vital signs after a grueling 23 hour heart transplant surgery, while one of his assistants, can be seen asleep in the corner of the operating room.

This iconic photo by James Nachtwey captures Polish cardiac surgeon Dr. Zbigniew Religa after performing the country’s first successful heart transplant, a 23-hour procedure. The assistant asleep in the corner underscores the immense physical toll on the surgical team.