When Julius Caesar and the Romans adopted the Egyptian, 365-day calendar, they soon realized that a solar year is actually 365.24 days long. 

Thus leap year, and leap day, were born.

Here are some fun facts about leap day:

• Approximately 4 million people worldwide are leap day babies
• Leap day babies are often called leapers or leaplings
• Odds of being a leap day baby are 1/1,461
• Among the famous people born on leap day are: Pope Paul III (1468), ‘William Tell’ and ‘Barber of Seville’ composer Gioacchino Rossini (1792), singer Dinah Shore (1916), motivational speaker Tony Robbins (1960) and rapper/actor Ja Rule (1976).
• There will be no leap year between 2096 and 2104
• Women often choose leap day to propose to the men in their lives. This has been attributed to and old Irish legend involving a deal struck by St. Brigid with St. Patrick. In some cultures, a man refusing such a proposal was expected to pay a penalty.