2020 is a leap year, and that means we all get to enjoy an extra day at the end of February. The leap day in the western secular calendar was introduced by Julius Caesar as a way to keep the calendar of the times synchronized with the Earth's rotation around the Sun. But for hundreds of years, the leap day was on February 24 and not February 29.

Matching the Earth's Revolution

Leap years aren't just used in the Gregorian calendar. Other cultures and other religious calendars also use leap days and leap months to keep their calendar synchronized with the Earth's revolution around the Sun.