Greenwich Observatory

Greenwich Observatory, located in London, is a historic astronomical facility famous for its role in defining global time and navigation. Established in the 17th century, it houses the Prime Meridian, the reference line for longitude at 0°, used to measure east and west across the globe. The observatory was vital for developing precise timekeeping and mapping the heavens, which facilitated accurate navigation and international coordination. Today, it is a museum and a symbol of scientific progress, offering visitors insight into astronomy, navigation, and the history of science. Its location at the Prime Meridian makes it a key site in understanding Earth’s geographic coordinate system.