Greenwich: Why Zero Longitude Is an Agreement

No natural line declares itself the start of longitude. Greenwich connects observation, navigation and the adoption of a shared coordinate reference.

Understand longitude

A meridian joins the poles; longitude describes east or west from a chosen origin. The courtyard line makes that idea visible.

Your phone may differ

The historic line and modern satellite reference do not coincide exactly. A non-zero GPS reading does not itself mean a broken phone. Check the coordinate system first.

Add context

Explore instruments and their maritime role. Check access to individual buildings and the courtyard rather than assuming one ticket covers the park and everything inside.