Time zones are surprisingly complicated. There are only 24 hours in a day, and yet there are more than 24 time zones in this world. Dealing with time zones is a reality of travel - both domestic and international. They can mess with one's circadian rhythm while traveling and lead to jet lag (although that's also partly the pressurization of the airplane's cabin).

People with friends around the world are constantly having to battle with people in different time zones. And it is the bain of setting up international conference calls. To make matters worse, many people don't even refer to their time zone by its international name - but by its local name. E.g. NYC's EST is actually internationally known as UTC -5 (formerly GMT -5). Imagine if everyone did that - so someone from Sydney just said "AEST" and not UTC + 10 (formerly GMT +10) and hung up the phone.

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How Time Zones Were Standardized

In the old days, every town would have its own time that could be different from the next. When one had to walk from one city to the next, it didn't matter if their time was 10 minutes different from the time recorded in one's hometown.

In 1675 the Royal Observatory, Greenwich was founded just out of London and they established the Greenwich Mean Time (GMT) - it was just another time kept in England. But that all changed with the advent of the Industrial Revolution and the development of the railways.

  • GMT: First Established In 1675

Railways had to be kept on a consistent time and it wouldn't do if every city had its own time. Eventually, the railways started to use GMT by using portable chronometers and this became standard and called Railway Time in Great Britain.

  • Railways: Scheduled Using GMT

By 1855, 98% of Great Britain's public clocks were using GMT - although it only became legal on August 2, 1880. Before that, there were even some clocks with two-minute hands - one for the local time and one for GMT.

Eventually, all time zones in the world were based on GMT, all time zones are GMT + or - increments of time (normally an hour) depending on their longitude. New Zealand adopted GMT in 1868 with it GMT+ 11 Hours and 30 Minutes.

Related: 15 DIY Hacks To Get Over Jet Lag Fast (5 Things That'll Make It Worse)

Time Zones Splitting Up The World

Today people take it for granted that all the world is offset by increments of an hour (or divisions of an hour) - and not say 6 minutes differentials. Today all time zones are fixed to GMT.

So while the world has the Royal Observatory and train schedules to thank for a fixed point from which to measure time, time zones are still complicated. There are time zones that sometimes don't even follow political borders. In the United States, counties can be in a different time zone to the rest of the state - like the Indiana counties close to Chicago are on Chicago time and not on the rest of the state's time.

  • Hoover Dam: Has Two Time Zones
  • China: Is On Only One Time Zone
  • Russia: Has Eleven Time Zones

While in the USA a state may be split into different time zones, China is in only one time zone. For them, they seek to emphasize that they are a united country and are not divided by time zones. As China is a massive country, the result is the sun can rise and set at some rather odd times in the western part of the country.

While New Zealand is basically in one time zone, it has some small islands offshore that are on a 15 minute time offset for some reason.

Related: 20 Essential Things To Know When Booking An International Flight

The Strange Case Of The International Date Line

The tiny American island of Little Diomede in Alaska's Bering Strait gazes across at the Siberian Big Diomede Island. Between them, is 2.5 miles of water and the International Date Line. Basically, the Russian Big Diomede Island is always "tomorrow."

  • Tomorrow: People Living In Little Diomede See Tomorrow By Looking At The Neighboring Island

Another oddity is the International Date Line that runs through the Pacific. One can fly on a 14 hour and 20-minute flight from Melbourne, Australia to Los Angeles and arrive have to wind one's clock back 4 hours from when one bordered the plane! If one bordered the place at 18.00 Wednesday, one flys for 14.5 hours and arrives at around 14.00 Wednesday. Of course, going the other way and one will lose a day.

Cross The International Date Line:

  • Fly East: Gain A Day
  • Fly West: Lose A Day

This means that it is perfectly possible to celebrate New Year in New Zealand, then board a plane, fly back to last year in Hawaii and celebrate it all over again. Alternatively, one could just walk over the county line or across the Hoover Dam to count the New Year in again.

Next: New App Helps You Avoid Jet Lag And Adjust To New Time Zones