ENGLISH SPEAKING COUNTRIES
The Historic Settlement of Greenwich
Tourist Attractions
Home of the Royal Observatory, Greenwich is a famous tourist destination because Greenwich Mean Time (GMT) is a term originally referring to mean solar time at the Royal Observatory in Greenwich.
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. Most time zones were based upon this reference as a number of hours and half-hours "ahead of GMT" or "behind GMT".
Source: Wikipedia
Here is a list of more pages about the United Kingdom: