In Greek mythology, the container associated with Pandora is a pithos, not a box.
A pithos was a large ancient Greek storage jar, commonly used for grain, oil, wine, or other supplies. Hesiod’s Works and Days describes Pandora releasing troubles from such a vessel, using the Greek word pithos. The text does not describe a small hinged box.
The “box” wording became widespread after later translations and retellings. A famous Latin rendering associated the vessel with a container that could be understood as a box, and that version became standard in European popular culture. The original Greek image was much larger and more practical than the familiar decorative box.
Pithoi were important archaeological objects because they stored food and liquids in homes, palaces, and sanctuaries. Their size and weight made them generally stationary, unlike the portable boxes shown in many modern illustrations.