Nearly every four years, we add an extra day to the calendar in the form of February 29, also known as Leap Day.

These additional 24 hours are built into the calendar to ensure that it stays in line with the Earth’s movement around the sun.

While the modern calendar contains 365 days, the actual time it takes for Earth to orbit its star is 365.2421 days.

To ensure consistency with the true astronomical year, it is necessary to periodically add in an extra day 

Here Are Some Things You May Not Have Known About Leap Day...

1. Many ancient calendars had entire leap months

2. Julius Caesar introduced Leap Day, with help from the Egyptians...

3. ...but their math was a little off.

4. Leap Day is often associated with marriage, proposals and flipping gender roles

5. People born on Leap Day are called 'Leaplings'