We made our way up the steep hill to the Greenwich Observatory, which is an iconic institution and treasured part of history and has played a pivotal role in the development of modern astronomy and timekeeping. It made me realise how difficult it was to solve the problem of navigation and timekeeping as for decades astronomers and instrument makers at the observatory grappled with the complexities of developing instruments that could withstand the harsh maritime conditions and maintain accuracy during turbulent voyages.

One of the most significant contributions of the Greenwich Observatory to the world is the establishment of the Prime Meridian, the line of 0 degrees longitude. In 1884, the Greenwich Meridian as the prime reference point for global timekeeping, giving birth to Greenwich Mean Time (GMT), which is the basis for the time zones we use today.

So as you walk into the observatory you first see the Prime Meridian, so I decided to take a walk  along the metal strip in the ground. 

With one foot in the Eastern Hemisphere, the other in the Western, I walked the line (a little like walking the plank) 

Did you know if you're wearing a watch while straddling the Prime Meridian, don't be surprised if it starts having an identity crisis. It'll tick in the Eastern time zone one second and then jump to the Western time zone the next. Time flies when you're confusing your watch. Ha Ha.. give it go if you're there.

Before the establishment of the  Meridian almost every town in the world kept its own local time. There were no national or international conventions which set how time should be measured, or when the day would begin and end, or what length an hour might be. So very confusing right?