Memento mori — “remember that you must die” — names a family of contemplative practices that take the inevitability of one’s own death as a daily object of attention. The practice has surfaced in many traditions independently. In late Roman antiquity, a slave reportedly walked behind a victorious general during his triumph, whispering memento mori in his ear. The desert fathers and the medieval Christian devotional tradition formalised the practice through skull imagery, the ars moriendi manuals, and the daily examen. In the early Buddhist canon, maraṇasati — mindfulness of death — is among the ten recollections taught by the Buddha. In the Stoic tradition, Marcus Aurelius writes in the Meditations of preparing each act as if it were one’s last. The contemporary practice — sustained in monastic communities, in palliative-care settings, and in the death-positive movements of the past two decades — preserves the same paradox: the steady contemplation of one’s mortality produces, not despair, but a sharpened attentiveness to what is here. The Academy holds memento mori as a Wonder because its central insight cannot be argued for; it can only be undergone.