1 November 17

It's Prime Meridian Day! On this date in 1884, representatives of 25 nations met in Washington, D. C., to adopt the convention that the meridian through London, England would be designated as the (only) Prime Meridian, longitude = zero degrees. (The final vote was 22-1, with two abstentions.) Without that standard, global navigation, timekeeping and communication would be far more complicated.