The "Dia da Toalha," or Towel Day, is an annual celebration that takes place on May 25th. It is a humorous tribute to the late British author Douglas Adams, who is best known for his science fiction series, "The Hitchhiker's Guide to the Galaxy." Towel Day is celebrated by fans of Adams and his work around the world.

The significance of the towel in "The Hitchhiker's Guide to the Galaxy" is explained in the book itself. According to the guide, a towel is one of the most useful items a hitchhiker can have. It can be used for various purposes, such as drying oneself off, wrapping around one's head for protection from harmful fumes, or signaling for help. Therefore, the towel has become a symbol of preparedness and resourcefulness for fans of the series.

On Towel Day, fans carry towels with them wherever they go, as a way of expressing their appreciation for Douglas Adams and his literary legacy. Some fans participate in organized events and gatherings, while others simply display their towels in public or share photos on social media using the hashtag #TowelDay.

Towel Day is not only a celebration of Douglas Adams, but also a way for fans to connect with each other and share their love for "The Hitchhiker's Guide to the Galaxy." It is a lighthearted and fun-filled day that brings together people who appreciate Adams' wit, humor, and unique perspective on the universe.