The Airy meridian marked as the “Prime Meridian of the World” (dotted line), and the modern reference meridian indicating zero longitude using GPS (solid line). (Imagery © 2014 Google Maps, Infoterra Ltd. & Bluesky)

The Prime Meridian isn’t Where You Think it is

Elizabeth Borneman

The true Prime Meridian is located about 334 feet east of the current Airy Transit Circle at the Royal Observatory in Greenwich, England.