National K9 Veterans Day, March 13, is a day set aside to honor commemorate the service and sacrifices of American military and working dogs throughout history.

It was on March 13, 1942, that the Army began training for its new War Dog Program, also known as the "K-9 Corps," according to American Humane, marking the first time that dogs were officially a part of the U.S. Armed Forces.

Show your support by using hashtag #NationalK9VeteransDay on social media.

Photo Credit: US Air Force