The Royal Observatory

The Royal Observatory in Greenwich, London, is a historic scientific institution best known as the home of Greenwich Mean Time (GMT) and the Prime Meridian, the line of 0° longitude that divides the eastern and western hemispheres of the Earth. Founded in 1675 by King Charles II, the observatory was established to improve navigation at sea by providing accurate astronomical data. Its first Astronomer Royal, John Flamsteed, laid the foundations for precise star mapping, and over the centuries it became a world-leading center for timekeeping and astronomy. Today, the Royal Observatory is a popular museum where visitors can stand astride the Prime Meridian, explore historic telescopes, and learn how astronomy and navigation helped shape modern science and global travel.