What is Greenwich Mean Time ?
For thousands of years, people have measured time based on the position of the Sun. It is noon when the Sun is highest in the sky. Sundials were the main source of time information into the Middle Ages. Then, mechanical clocks began to appear. Cities had town clocks, which would be set by measuring the position of the Sun. Every city was on a slightly different time. Great Britain became the first country to set a standard time throughout a region when it established the Greenwich Mean Time standard in the 1840s. The railways cared most about the inconsistencies of local time. They forced the uniform time on the country. A railway adopted the time in 1840 and by 1847 most used it. By 1855, most public clocks in Britain were set to GMT, although some had two minute hands, one for local time and one for GMT. The legal system adopted GMT in 1880. Because Great Britain was the major world power at the time, it placed the center of the first time zone at England’s Royal Greenwich Observator
