Christiaan Barnard performed on 3 December 1967 the first human heart transplant, implanting the heart of a brain-dead donor into a patient with terminal heart failure. The recipient lived 18 days. The operation was technically successful and its impact transcended surgery: it triggered global debates on brain death, transplant immunology, and medical ethics. In the surgical tree, it represents the transition from repairing and revascularizing to replacing the entire organ.