HistoryAncient (c. 150-100 BCE)Greece / Mediterraneanhigh confidence

The Antikythera Mechanism used precisely cut, independently rotating gears in a system known as epicyclic gearing, a technology not otherwise known to exist in the West for another 1,500 years.

Notes on verification

Well-corroborated by peer-reviewed research (Freeth et al., Nature 2006) and consistent scholarly consensus. The 1,500-year gap is a commonly cited approximation; exact figures vary (1,300-1,500 years) depending on comparison point, but the core claim is solid. [tier=silver indep_score=0.925 clusters=2 claim_tier=notable]

Sources