On the off chance you suddenly find yourself hitchhiking through the galaxy, there is one item you’ll always need to have with you: a towel! In celebration of Douglas Adams and his classic Hitchhiker’s Guide to the Galaxy series, we
encourage you to carry around a towel with you for the entirety of the day
Established in 2001, two weeks after the passing of the celebrated author, Towel Day is celebrated by countless humans (the third most intelligent creatures on the planet.) No word on whether the dolphins or the mice find a need to carry around a towel.
More here at the Towel Day website.