Happy Leap Year! People around the world are celebrating today's leap day as an extra day in the year - or another day at work, if you're a cynic.
But how much do you actually know about leap years?
February was the one month in the Gregorian calendar which lost out - all thanks to Emperor Augustus' ego - leaving it with less days than the others.
The month did initially have 30 days, but Augustus stole two of them to add to "his" month of August.
The extra day is now added to February to adjust for the fact that the Earth does not take exactly 365 days to orbit the sun.
Test your knowledge of leap years with our quiz...