Follow these links to learn more about world time zones and related topics:

1.  https://www.timeanddate.com/time/what-is-a-time-zone.html
2.  https://www.timeanddate.com/time/time-zones.html
3.  https://www.timeanddate.com/time/time-zones-history.html
4.  https://www.timeanddate.com/time/standard-time.html
5.  https://www.timeanddate.com/time/dateline.html
6.  https://en.wikipedia.org/wiki/Time_zone