What would our life be like without calendars? We wouldn't know when to celebrate birthdays, be able to plan holidays, or even show up for important events. People realized the importance of keeping track of days and months centuries ago. Some ancient calendars followed the cycles of the moon, while others focused on the movements of the sun. Today, we use the modern Gregorian calendar as our primary system. But did you know that alongside this trusty timekeeper, there's a whole bunch of other ancient calendars still kicking around?

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