Stop 84 of 109 · Where the Day Begins
1884 · Washington, International Meridian Conference
The Vote That Made Greenwich the Center of Time
In 1884, delegates from twenty-five nations met in Washington to pick one line as the world's zero meridian, and nearly everyone already agreed on the answer.
For most of history, every country was free to measure longitude from wherever it liked: Paris, Cádiz, Rome, its own capital. Sailors, in practice, had already settled the question: by the 1880s, a survey found that roughly 72 percent of the world's shipping, by tonnage, navigated using charts based on the meridian running through the Royal Observatory in Greenwich.
So when delegates from 25 nations met at Washington's International Meridian Conference in October 1884, Greenwich was less a proposal than a formality waiting to be confirmed. The vote to make it the world's prime meridian passed 22 to 1. Only San Domingo, now the Dominican Republic, voted against; France and Brazil abstained.
France's abstention wasn't really about geography: Paris had its own national observatory and considerable pride at stake. It took nearly thirty years to fully concede the point, and even then, gracefully: a French law of 1911 defined legal time as "Paris mean time, retarded by nine minutes twenty-one seconds," which is, worked out precisely, Greenwich time by another name.
The conference didn't create time zones. Those were worked out later, by separate convention. What it fixed was the zero line every zone is still counted from. Every "GMT+" or "GMT-" on a phone or a watch today traces back to that one vote in Washington.