Rat Catcher's Day is an informal holiday observed worldwide, commemorating the legend of the Pied Piper of Hamelin. It recurs every July 22 in the United States, while a similar celebration takes place on June 26 in Hamelin, Germany, where the legend originated. The myth tells of a piper who lured away rats from the town with his music, but when the mayor refused to pay him, the piper took revenge by leading 130 children away, never to be seen again. This tale has inspired numerous writers, including the Brothers Grimm and Robert Browning. In Hamelin, a festival dedicated to the Pied Piper is held annually on June 26, marking the date the children were said to have vanished in 1284. The observance of Rat Catcher's Day serves as a reminder of this enduring legend and its cultural impact.