In Greek mythology, hope remained inside Pandora’s opened jar after troubles escaped.
The detail appears in Hesiod’s Works and Days, the earliest surviving literary source to tell the complete Pandora story. Zeus sent Pandora to Epimetheus as part of the punishment imposed on humanity after Prometheus stole fire. Pandora opened the storage vessel, releasing many evils into the world, but a final substance stayed inside before she could release it.
English translations usually call that substance “hope,” based on the Greek word elpis. The episode is debated because the text does not simply state that hope is a benefit; hope can be understood as either a comfort left for humans or another condition trapped among them. Also, Hesiod described a jar, not a box. The familiar phrase “Pandora’s box” arose later through translation history, especially through Erasmus’s Latin wording.