Name the main longitude line at O degrees

The main longitude line at 0 degrees is known as the Prime Meridian. It runs from the North Pole to the South Pole and passes through Greenwich, London. This imaginary line is also the basis for the world's time zone system—the world is divided into different time zones based on hours ahead of or behind Greenwich Mean Time (GMT). Fun fact: The establishment of the Prime Meridian in 1884 was a significant moment in history, as it provided a standardized reference point for navigation, mapping, and communication. Before that, different countries had their own prime meridians, which led to confusion and inaccuracies in global positioning!