To fix this the Royal Observatory decided to set a standard ... the other in the Western Hemisphere at the same time! The Prime Meridian is an imaginary line that runs around the Earth.

The Royal Observatory Greenwich is the home of Greenwich Mean Time and the Prime Meridian of the World. It is also home to London's only planetarium, the Harrison timekeepers and the UK's largest ...

The competition, which is run by the Royal Observatory Greenwich in London—the home of Greenwich Mean Time and the Prime Meridian—attracted 4,000 entries this year from amateur and ...

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