Where was the international prime meridian officially designated?

The international prime meridian was officially designated at the International Meridian Conference, which was held in Washington D.C. in 1884. During this conference, it was agreed that the prime meridian would pass through the Royal Observatory in Greenwich, England. This line became known as the Greenwich Meridian, or Longitude Zero (0° longitude). The selection of the Greenwich Meridian as the international prime meridian meant that it would serve as the starting point for measurement of longitude and time zones around the world.

The concept of a prime meridian is crucial for establishing a universal time system and for creating a reference point from which longitudinal coordinates can be determined. Longitude is the geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is measured in degrees, minutes, and seconds, with the prime meridian defined as 0° longitude. All other longitudes are measured up to 180° east or west from this line. The Earth is divided into 24 time zones based on the prime meridian, and as you travel east or west from Greenwich, the time changes by one hour for each 15° shift in longitude. The concept of a prime meridian, along with the latitude lines, which run east-west, helps with navigation and also plays an integral role in global communication and timekeeping. Before the prime meridian was established, different countries used their own meridians for navigation, which led to confusion and difficulty in coordinating travel and trade. The adoption of the Greenwich Meridian helped standardize maps and timekeeping, which was becoming increasingly important with the advent of international travel and commerce.