Why Greenwich Became the Prime Meridian: The Story of Longitude and the Royal Observatory

The historic observatory at Greenwich is now a museum, but how did it get to be the historic Prime Meridian (the zero longitude line that divides the Earth into eastern and western hemispheres for navigation) of the world?  Why a relatively obscure place in South London?  This animated short, created by the Royal Observatory, delves into its history and explains these and other questions getting a little existential – why does it even exist at all? It all boils down to longitude – the measure...