It's February 29, and while some peoples' great grandads are celebrating their 21st birthdays, we've scoured the internet to bring you some interesting facts about the leap day.

Firstly, a leap day was introduced to correct the calendar as the exact time the Earth takes to complete a full circle around the Sun is a little longer than a year. In fact it takes 365 days, 5 hours, 48 minutes, and 46 seconds.

Reportedly, it was the Romans who first designated February 29 as the leap day. Later, a more precise formula was adopted in the 16th century when the Gregorian calendar fine-tuned the calculations to include a leap day in years only divisible by four.

In the British Isles, it is a tradition that women can propose marriage only on leap years.

Supposedly, a 1288 law by Queen Margaret of Scotland (then age five and living in Norway), required that fines be levied if a marriage proposal was refused by the man. Compensation ranged from a kiss to £1 to a silk gown, in order to soften the blow.

In some places the tradition was tightened to restricting female proposals to the modern leap day, February 29, or to the medieval leap day, February 24.

In Denmark, the tradition is that women may propose on the bissextile leap day, February 24, and that refusal must be compensated with 12 pairs of gloves.

In Finland, the tradition is that if a man refuses a woman's proposal on leap day, he should buy her the fabrics for a skirt.

In Greece, marriage in a leap year is considered unlucky.

Sundays that fall on the 29th of February happens only every 28 years. The last one was in 2004, the next would be in 2032.  

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