Every year, on August 5, National Underwear Day is celebrated around the country.

You would think that you know about underwear, since you’ve been wearing it since you got out of diapers, but do you know the history of these undergarments? According to Local Histories, men wore linen shorts, known as braies, during the Middle Ages. Under their clothes, women wore a shift. Pants were long drawers that covered the entire leg in the United Kingdom. Women’s knickers, on the other hand, did not debut until the nineteenth century.

National Day Calendar tells us that National Underwear Day was founded in 2003. Maybe this year, you could gather a group of your boldest, most unconventional friends and have a fun parade in someone’s backyard. A National Underwear Day Parade has taken place publically in New Orleans for several years.

Maybe you’re not bold enough to be in or watch a parade on National Underwear Day, but there are so many underwear designs that can make you feel like a kid again. Why not pull up your big girl panties and celebrate in your own private way?