What is the starting point for longitude?

The prime meridian is the starting point for measuring longitude. It is an imaginary line that is designated at 0 degrees longitude and runs from the North Pole to the South Pole, passing through Greenwich, England. Longitude is used to determine how far east or west a location is from this reference line. The prime meridian divides the Earth into the Eastern and Western Hemispheres, providing a clear and standardized starting point for navigation and mapping purposes. Understanding the significance of the prime meridian is essential for geographical orientation, as it helps in charting courses for travel and defining time zones around the world.