Why Do We Even Have A Leap Year?

(CNN) — 2020 is a leap year, which means we get to enjoy a whole extra day of February, and people born on February 29 finally get some presents.
But why do we even have leap years?
Our calendar has 365 days in a year, because that’s pretty much how long it takes the Earth to orbit the Sun. The problem is that in reality it takes the Earth around 365 ¼ days (actually 365.24219 days) to circle the Sun (that’s a solar year), which means our calendar is out by around a quar