I visited the city of Greenwich, the home of Greenwich Mean Time......and Meridian 0 0 0. a standard set for the entire world. Think what it would mean if it hsdn't been standardized......
The walk up to the Royal Observatory was worth it loved looking out over Greenwich and seeing the green laser light extending out into the sky of what is longitudinal meridian 0 0 0. An amazing thing to consider...... and it was a wonderful day!
History
As the United Kingdom grew into an advanced maritime nation, British mariners kept at least one chronometer on GMT in order to calculate their longitude from the Greenwich meridian, which was by convention considered to have longitude zero degrees (this convention was internationally adopted in the International Meridian Conference of 1884). Note that the synchronization of the chronometer on GMT did not affect shipboard time itself, which was still solar time. But this practice, combined with mariners from other nations drawing from Nevil Maskelyne's method of lunar distances based on observations at Greenwich, eventually led to GMT being used worldwide as a reference time independent of location. Most time zones were based upon this reference as a number of hours and half-hours "ahead of GMT" or "behind GMT".
Greenwich Mean Time was adopted across the island of Great Britain by the Railway Clearing House in 1847, and by almost all railway companies by the following year, from which the term "railway time" is derived. It was gradually adopted for other purposes, but a legal case in 1858 held "local mean time" to be the official time. This changed in 1880, when GMT was legally adopted throughout the island of Great Britain. GMT was adopted on the Isle of Man in 1883, Jersey in 1898 and Guernsey in 1913. Ireland adopted Greenwich Mean Time in 1916, supplanting Dublin Mean Time. Hourly time signals from Greenwich Observatory were first broadcast on 5 February 1924, rendering the time ball at the observatory obsolete in the process.
There is a great website on the history of time
http://physics.nist.gov/GenInt/Time/world.html