Are you a 'leapling'? No, not like this Eurasian red squirrel; rather, that's the term for anyone born on leap day. A leap year is a calendar oddity that exists because Earth's orbit and our usual year count are slightly out of sync. Earth takes 365.25 days to revolve around the sun. To compensate for those extra 5 hours, February gets an extra day—leap day—every four years. The concept, dating back to the ancient Romans, was refined in the Gregorian calendar, introduced in 1582 by Pope Gregory XIII. While the purpose of the day is to keep our year aligned with the solar calendar, it can also serve as an extra day to prepare for spring! Cultures worldwide mark leap days and years with unique customs. In Ireland and Britain, women propose to men, in Greece, marrying during a leap year is said to bring misfortune, and in France, a satirical newspaper is published.