Leave no stone unturned

To exhaust every possibility or effort in pursuit of a goal, searching thoroughly without overlooking anything, driven by determination or desperation. It's like flipping every rock for a hidden clue, with a tone of relentless zeal or meticulous care, used for investigations, solutions, or quests.

From ancient Greece, in Euripides' 412 BCE play 'Heracles,' where a character vows to 'leave no stone unturned' seeking a lost friend-echoed in a tale of treasure hunters flipping stones after an oracle's hint. English adopted it by the 1540s, as in a 1542 translation urging total effort. It reflects classical diligence and Renaissance curiosity, growing into a proverb for exhaustive search in a detail-obsessed age.