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, origin, deals and more.

Eventually, the calendar we all know was adopted by Pope Gregory XIII in 1582, and it's changed little since then — not that the system is flawless. February gets a leap year once every four years to ...

Leap Year ensures it remains that way, explains Duke physics professor Ronen Plesser in this short video. Plesser breaks down the math behind adding a day to the calendar every four years so that we ...

Eventually, the calendar we all know was adopted by Pope Gregory XIII in 1582, and it's changed little since then — not that the system is flawless. February gets a leap year once every four ...