The Prime Meridian passes through which London district?

The Prime Meridian passes through Greenwich, a district of London.

Greenwich became associated with zero longitude because the Royal Observatory established there used a reference meridian for astronomical observations, navigation, and timekeeping. In 1884, the International Meridian Conference in Washington, D.C., selected the meridian through Greenwich as the world’s standard prime meridian. It consequently became the reference for measuring longitude east and west.

The famous line marked at the Royal Observatory follows the historic Airy transit circle, first used in 1851. GPS and modern geodetic systems use the IERS Reference Meridian instead, which lies about 102 meters east of the traditional Greenwich line because modern measurements account for differences in reference systems and local gravity.

Greenwich also gave its name to Greenwich Mean Time, although international civil time is now based on Coordinated Universal Time. The district is part of the Royal Borough of Greenwich and contains Maritime Greenwich, a UNESCO World Heritage Site that includes the observatory, the Royal Naval College, and the Queen’s House.