Feb. 29 is a date that happens only once every four years, but what are leap years? Why do we need them? And how did they come about? Leap years are years with 366 calendar days instead of the normal ...

Feb. 29 comes only once every four years (most of the time), but why do we need leap years and how did they come about? When you purchase through links on our site, we may earn an affiliate commission ...