Perhaps you’ve heard that today is National Dog Day. According to the website devoted to the occasion, it was founded in 2004 to honor dogs for “their endearing patience, unquestioning loyalty, for their work protecting our streets, homes and families.”

The holiday sparked the hash tag #NationalDogDay, in which Twitter users posted photographs of their favorite dogs. And that quickly turned to veterans and U.S. service members sharing pictures of military working dogs and other canines they encountered while deployed.

Consider this first one, from colleague Thomas Gibbons-Neff:

The Pentagon’s official account also got in on the act:

So did the Air Force and the Marines:

And the Defense Department Inspector General’s office:

Here are a few examples of dogs at work:

And some examples of military service dogs getting love:

Happy National Dog Day.