There’s a good chance that morning came pretty early for you today. And if you’re a parent, it came even earlier, since you spent most of the night trying to convince your children to go to  sleep last night. Because somehow, moving bedtime up an hour, makes them “not tired” for three.  Twice a year, time-changes enter our lives and shake things up a little.

Here are 13 things you probably didn’t know about this biannual event.

1. We all tend to call it Daylight Savings Time, but the term is actually Daylight Saving Time (DST) without the “s.” Many places in Europe call the time change “Summer Time.”

2. Most people think that DST has something to do with plants or cows or something that happens on a farm. In fact, it has nothing to do with agriculture. DST started as a way to save energy by using more of the evening daylight available during summer.

3. Ben Franklin is sometimes credited for the idea of DST. It’s true that he wrote a satirical paper about “Early to bed, Early to rise…” when he noticed that the people in France surrounding him slept half the day away. Others noticed the same thing through the years including William Willet. He was the first guy to try to get time moved up an hour. He actually brought the bill before the House of Commons in 1908 and many other years. They denied him. Every time.

4. The first country to use a time change to save energy and hence, barrels of coal used to produce it, was Germany during World War I. Many countries followed their example.

5. During World War II, the US kept Daylight Saving Time in place for over three years, from February 1942 through December 1945, in order to save energy for the war effort.

6. Every year, state governments see bills to keep or get rid of DST. Opponents, traditionally agricultural and night dependent businesses like movie theatres, cite disruption to circadian sleep cycles, health issues, and costs. Proponents, traditionally retailers, sports organizations, and tourism, point to energy savings, increased outside activities, and decreased TV viewing.

7. The Energy Policy Act extended DST by four weeks.

8. Most North American and European countries employ DST. Most South American, African, and Asian countries do not. Only Kyrgyzstan and Iceland keep it year round.

9. Countries at the poles and the equator don’t generally need any time change. Light at the poles is extreme in either season. Light at the equator stays pretty much the same in any season.

10. Two countries take holidays into account when changing the time. Morocco will not make light last later until after Ramadan. Brazil will work the change around Carnival.

11. Honduras charts one of the shortest stretches of later light, three months, from May 7, 2006 to August 7, 2006.

12. Europe has three separate time zones that all change their clocks at the same time.

13. In the Southern Hemisphere, Daylight Saving Time runs from October to March.