While thousands of meridians exist, a few stand out for human geography:
However, unlike latitude, where 1° equals roughly 111 km everywhere, the distance between meridians shrinks as you move toward the poles. meridian longitude
The history of establishing a standardized system of meridians is a tale of scientific rivalry and geopolitical maneuvering. For centuries, mapmakers used different meridians as their zero point—often based on their nation’s capital city—creating chaos for international trade and navigation. The turning point came in 1884 at the International Meridian Conference held in Washington, D.C. Delegates from twenty-five nations voted to establish the Prime Meridian at the Royal Observatory in Greenwich, England. This decision was largely influenced by the fact that nearly three-quarters of the world's commerce already relied on nautical charts using the Greenwich reference. The establishment of the Prime Meridian (0° longitude) effectively bisected the world into the Eastern and Western Hemispheres and provided a singular anchor for global mapping. While thousands of meridians exist, a few stand
For precise navigation, degrees are broken down: The turning point came in 1884 at the
: Unlike lines of latitude (parallels), all meridians meet at the poles. Variable Distance
Without the system and the IDL, global synchronization would be impossible. You would have ships arriving on "Mystery Monday" while their home port was on "Tuesday."