Articles About History (21)
![Illustration image](http://c.tadst.com/gfx/150x84/utc-prime-meridian-.jpg?1)
UTC: The World’s Time Standard
Coordinated Universal Time (UTC) is the basis for civil time today. This 24-hour time standard is kept using highly precise atomic clocks combined with the Earth's rotation.
![Parents playing with their young daughter in the evening sun](http://c.tadst.com/gfx/150x84/evening-family.jpg?1)
History of DST
History of Daylight Saving Time (DST). Why was Daylight Saving Time created, who invented it, and what is the point of having a time change every year?
![Tourists visiting the Papal Basilica of St. Peter in the Vatican City Rome, Italy - November 2015. Tourists visiting the Papal Basilica of St. Peter in the Vatican City Rome, Italy - November 14, 2015](http://c.tadst.com/gfx/150x84/italy-rome-vatican-.jpg?1)
The Gregorian Calendar
The Gregorian calendar is the internationally accepted civil calendar that was first adopted in 1582.
![Storm rising over United States Capitol Building, Washington DC](http://c.tadst.com/gfx/150x84/united-states-capitol-building.jpg?1)
DST in the United States
When did Daylight Saving Time start in the US? Which states use it, and why?
![Astronomical clock in Prague, the Czech Republic.](http://c.tadst.com/gfx/150x84/clockprague.jpg?1)
When Did DST Start in Europe?
Daylight Saving Time (DST) was first adopted in Europe by Germany in 1916.
![Bronze statue of Bolognese Pope Gregory XIII in Accursio Palace Bologna](http://c.tadst.com/gfx/150x84/pope-gregory.jpg?1)
Gregorian Calendar Reform: Why Are Some Dates Missing?
The Gregorian calendar was introduced in 1582 in some countries. The US, Canada, and the UK changed in 1752. Why were some days skipped?
![Illustration image](http://c.tadst.com/gfx/150x84/time-zone-map-history.jpg?1)
Why Do We Have Time Zones?
The expansion of transport and communication during the 19th century created a need for a unified time-keeping system, and time zones were introduced.
![Fireworks at night over a bridge. Boats on the river under the bridge.](http://c.tadst.com/gfx/150x84/fireworks-night-sydney.jpg?2)
When Did the 21st Century Start?
When did the 3rd millennium and 21st century begin: on New Year's Day 2000 or 2001? Do we count from year 1 or year 0 AD? What century are we in?
![A sundial with the Sun casting a shadow. A sundial with the Sun casting a shadow.](http://c.tadst.com/gfx/150x84/sundial-local-mean-time.jpg?1)
What Is Local Mean Time?
Use a sundial to determine the time of day and you will probably be off by a few minutes. That's where LMT comes into play. How is it measured and what is it used for?
![Illustration image](http://c.tadst.com/gfx/150x84/leapseconds.jpg?1)
What Are Leap Seconds?
Every now and then a leap second is added to Coordinated Universal Time (UTC) in order to synchronize clocks worldwide with the Earth's rotation.
![Prime Meridian line at the Royal Observatory in Greenwich, London](http://c.tadst.com/gfx/150x84/greenwich-meridian-02.jpg?1)
Is the Greenwich Meridian in the Wrong Place?
Why does a GPS device not show 0 degrees of longitude at the line marking the prime meridian in Greenwich, London, UK? Is it wrong—or just different?
![Sun peeking through trees with snow on the leaves and branches and snow on the ground.](http://c.tadst.com/gfx/150x84/december-solstice-winter.jpg?1)
December Solstice Customs
Learn more about the customs, traditions and events surrounding the December solstice.
![Real Earth Planet in yellow sun. Remodeled from real Earth NASA photo](http://c.tadst.com/gfx/150x84/time-universe-6.jpg?1)
Did the Mayan Calendar Predict The End?
The Mayan calendar ended one of its great cycles in December 2012, which has fueled countless predictions about the end of the world on December 21, 2012 at 11:11(UTC).
![Illustration image](http://c.tadst.com/gfx/150x84/stonehenge-june-solstice.jpg?1)
June Solstice Traditions
In many Northern Hemisphere cultures, the June solstice is associated with holidays, feasts and celebrations.
![Blue grapes on the vine at sunset.](http://c.tadst.com/gfx/150x84/ripe-grapes-harvest.jpg?1)
September Equinox Customs
Folklore, customs, traditions and holidays surrounding the September equinox.
![Easter Monday](http://c.tadst.com/gfx/150x84/easter-monday.jpg?1)
March Equinox Customs
Learn more about the customs, traditions and events surrounding the March equinox.
![On a 5th wedding anniversary, tradition dictates a gift made from wood, like this gilded trinket box. Save Download Preview A handmade gilded trinket box with vase and flower on a shabby chic background.](http://c.tadst.com/gfx/150x84/wooden-gilded-trinket-box.jpg?1)
Anniversary and Birthday Traditions Around the World
Anniversaries and birthdays are celebrated differnetly in different cultures around the world.
![A blurry businessman walking toward four clocks stock photo](http://c.tadst.com/gfx/150x84/man-clocks.jpg?1)
Understanding UTC Offsets
UTC, or Coordinated Universal Time, is a 24-hour global time standard used to determine time zones worldwide.
![People watching fireworks above a mountain village.](http://c.tadst.com/gfx/150x84/new-year-saas-fee.jpg?1)
When Do Decades Start?
Did the year 2020 mark the beginning of a new decade, or did the twenties begin on January 1, 2021?
![Roman numerals 1-5, numbers in Roman numerals, chart, short table](http://c.tadst.com/gfx/150x84/roman-numerals-table.png?1)
How To Write and Count Roman Numerals
To write any number in Roman numerals, combine the letters I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). Start with the highest number. For example, 2022 is MMXXII. MM = 2 x 1000; XX = 2 x 10; II = 2 x 1.
![The Sun shining through the Stonehenge ancient monument.](http://c.tadst.com/gfx/150x84/stonehenge-solstice2.jpg?1)
What Is a Calendar?
Calendar definition and meaning: Solar and lunar, tropical and sidereal – why did humans invent calendars? Current year in Gregorian, Muslim, and Chinese calendar.