Attribute 4
The work of John Flamsteed and others permitted accurate measurement of the Earth’s movement and contributed to the development of global navigation. The choice of Greenwich for the Prime Meridian in 1884 means that the Royal Observatory sits at the meeting point of the eastern and western hemispheres on a map of the world. It is a popular photographing opportunity for visitors to straddle the line. After dark a green laser beams out northwards along the Meridian line.