What is the common English expression for the ancient Greek story of Pandora’s jar?

The common English expression for the ancient Greek story of Pandora’s jar is “Pandora’s box.”

In modern English, “Pandora’s box” describes a source of unexpected problems that creates further consequences when opened or investigated. The expression comes from the myth recorded by Hesiod, although Hesiod described a pithos, or large jar, rather than a box.

The phrase became established through later translation, especially the use of the Latin word pyxis for the vessel. Over time, the box image became dominant in literature, art, education, and everyday speech. The expression is now often applied metaphorically to technology, politics, scientific discoveries, or decisions with unforeseen effects.

“Achilles’ heel,” “Midas touch,” and “Gordian knot” are also expressions from classical mythology or legend, but they refer to different stories. “Pandora’s box” specifically signals the opening of something that unleashes a chain of troubles.