According to Greenwich

Space and place in terms of individual experience and interpretation is usually different from space and place in terms of an empirical, coordinate-based interpretation. However, the two blend in an interesting way when examining the case of the Greenwich Prime Meridian and how its meaning has shifted through time and space. Up until the 19^th century, there existed 20 different prime meridians introduced by different countries in accord with their specific geography and area. The Greenwich Prime Meridian was introduced in 1884 following a conference of 20 nations, during which Britain was chosen to be the location of 0° 0' 00". Britain had a lot of power and influence at the time which was part of the reason why it was chosen to be the center of the world according to which all other nations would adjust their time to for a 24hour loop throughout the day.

Mid 19^th century, countries were beginning to be more connected through railways, which meant that they needed common time zones: the Prime Meridian created universality in terms of tracking time. However, in 1984, when science had the available technology to master the precision of time, the Greenwich Prime Meridian had to be shifted 100m east to keep in sync with the Earth’s rotation anomalies. Thus, the Prime Meridian is now a historical site of random choice of a starting point in comparison to the scientifically corrected Prime Meridian (although the newest location of the Prime Meridian is still based on the arbitrary point of Greenwich, just more precise).

This shift clearly illustrates the arbitrary nature of boundaries and points chosen by those in power. A quotation from the article precisely states, “Dr Ariel argues this [adjustment] renders the historical Prime Meridian no longer meaningful. But Dr Higgitt believes it simply highlights the fact it is not a scientifically-determined line and simply the result of global agreement.” This concept means that if Upper Canada was as influential as Britain was at the time, the Prime Meridian would be located here, and the world would go about in accord with Toronto.

http://news.bbc.co.uk/2/hi/uk_news/magazine/8266883.stm