Every day is a national day of something.

March 13 is National Jewel Day, Earmuff Day, Good Samaritan Day and Open an Umbrella Indoors Day, according to the National Day Calendar.

All that said, it's also a day that is worth observing: National K-9 Veterans Day.

WHY MARCH 13?

A retired military working dog trainer came up with the idea for the day, which falls on the birthday of the Army K-9 Corps formation in 1942, the National Day Calendar explained.

According to the publication, the United States realized the potential of military canines after seeing the Europeans use dogs as sentries and message carriers during WWI.

A private citizen launched the Dogs for Defense program, which worked with breeders and the American Kennel Club to train dogs for military use.

As demand grew, the military took over dog training. Over the years, working dogs became more widely used by law enforcement at home.

HOW TO OBSERVE: Use #NationalK9VeteransDay when you post or share on social media. You can also call your local law enforcement agency to find ways to donate to their K-9 programs.