Recently, social media users became surprisingly curious about one small detail found on almost every bath towel — the strange woven line near the ends.

Many people assumed it was only for decoration, while others joked that it separated the “face side” from the “body side” of the towel. The discussion quickly went viral as thousands joined in with funny theories and questions.But the truth is that the line actually has a real purpose. It’s called the “dobby border,” a tightly woven section designed to strengthen the towel and prevent the edges from fraying after repeated washing.

It also helps towels keep their shape, improves the balance between softness and absorbency, and even makes towels easier to fold neatly.

Besides being practical, the woven stripe also gives towels a cleaner and more polished appearance.

What seemed like a tiny, unimportant detail turned out to be a smart design feature that most people never noticed before.