They are fictions. But they are useful fictions—the scaffolding that allows a spinning rock to run on a schedule.
The Prime Meridian is the 0° line of longitude. It runs directly from the North Pole to the South Pole, passing through England, France, Spain, Algeria, Mali, Burkina Faso, Togo, Ghana, and Antarctica. prime meridian and antimeridian
But why Greenwich? In the late 1800s, sea travel was booming, but navigation was chaos. Every country used its own "prime meridian" (Paris, Berlin, Washington D.C.—everyone wanted to be the center). Finally, in 1884, 25 nations met in Washington D.C. and voted: Greenwich won. Mostly because the U.S. had already adopted it for its own rail networks, and 72% of the world’s shipping already used it. At the Greenwich observatory, you can literally stand with one foot in the Eastern Hemisphere and one foot in the Western Hemisphere. It is one of the most photographed feet-in-two-places spots on Earth. There is a giant steel line embedded in the courtyard, and a green laser shoots northward into the London sky every night. The Antimeridian: The Land That Time Forgot Now, spin the globe exactly 180 degrees away from Greenwich. You have arrived at the Antimeridian (180° longitude). They are fictions
I am talking, of course, about the and its lesser-known twin, the Antimeridian . It runs directly from the North Pole to
But two invisible lines on that grid tell a fascinating story of human ego, global cooperation, and literal time travel.