Cleveland Abbe
In order to compile his information, Abbe required a time-keeping system that was consistent among the stations. To accomplish this he divided the United States into four standard time zones. He published, in 1879, a paper titled "Report on Standard Time". In 1883, he convinced North American railroad companies to adopt his time-zone system. In 1884, Britain, which had already adopted its own standard time system for England, Scotland, and Wales, helped gather international consent for global time. In time, the American government, influenced in part by his 1879 paper, adopted the time-zone system.
Time in North Korea
On 29 April 2018, North Korean leader Kim Jong-un announced his country would be returning to to realign its clocks with South Korea. On 30 April 2018, the Supreme People’s Assembly of North Korea issued a decree about changing the time zone in North Korea as a further step in unifying Korea and eliminating differences between the South and North. The time zone change was applied at 23:30 on 4 May 2018 ().