What does the prime meridian signify in the context of geography?

The prime meridian signifies the starting point for time zones worldwide. It is defined as 0 degrees longitude and serves as a reference line from which all other longitudes are measured. This meridian runs from the North Pole to the South Pole, passing through Greenwich, England. As a result, local times around the world are calculated as a specific number of hours ahead of or behind Greenwich Mean Time (GMT), making it fundamental in global navigation and timekeeping.

The prime meridian plays a crucial role in standardizing time zones, facilitating international communication, travel, and trade. Understanding its significance helps in comprehending how the globe is divided into longitudinal sections, each representing a different time zone relative to GMT.