![global time zone map global time zone map](https://1.bp.blogspot.com/-mhOP5uD3KvE/XuiS_hBKtWI/AAAAAAAAQp8/n9g22Fu5w6YNk3vW_gva3SfunghBu2ypACK4BGAsYHg/s4000/World_Time_Zones_Map.png)
This means that time zone boundaries shift every time a country switches between standard time and Daylight Saving Time (DST). Other names: Universal Time Coordinated / Universal Coordinated Time. In contrast to most time zone maps out there, which are static, our map is dynamic and shows areas that currently follow the same local time. At noon, on November 18, 1883, telegraph lines transmitted GMT time to major cities where authorities adjusted their clocks to their zones proper time. By the 1800s, maps used leading national observatories (e.g., Greenwich observatory in England), a country’s most prominent maritime port or city (e.g., Philadelphia in the United States), or a religious site (e.g., Jerusalem or Saint Petersburg) to determine their 0o longitude marker. UTC / GMT is the basis for local times worldwide. That year, the United States was divided into four time zones roughly centered on the 75th, 90th, 105th, and 120th meridians.  For example, in the second century B.C., the Canary Islands were bisected by the prime meridian because these islands were believed to be the western extent of the world. Sky-gazers across North America are in for a treat on April 8 when a total solar eclipse will pass over Mexico, the United States and Canada. Different people and cultures used different primary reference lines throughout history. Current world time - check current time in more than 550 cities around the world at the Directory of World Time. Today, the prime meridian is located in Greenwich, England, but this primary reference line of longitude has not always been at its current location.
![global time zone map global time zone map](https://showme0-9071.kxcdn.com/files/358589/pictures/thumbs/626414/last_thumb1358380379.jpg)
The designation of a line of longitude as the prime meridian (0º) is arbitrary, unlike the degrees of the parallels of latitude that have their zero degree line along the equator, an actual physical feature.
![global time zone map global time zone map](https://printable-us-map.com/wp-content/uploads/2019/05/time-zone-map-for-usa-map-of-timezones-usa-lovely-united-states-time-printable-map-of-usa-time-zones.jpg)
The location of the prime meridian and the time zones demonstrate that even the most straightforward mathematical and scientific systems of classification and measurement are not immune to political arguments and boundaries.Â