This year is a leap year, meaning Feb. 29 was added as the 366th day on the calendar. Here's what to know about its meaning, ...

Every four years, an extra day is added to the calendar, But even with leap day, the math doesn't exactly, well, math.

Prior to the Gregorian and even Julian calendars ... emperor adopted a 365-day calendar and added 10 days the calendar, including a leap day in February every four years, calendar.com said.