1.25" with covered metal back stamped by maker "St. Louis Button Co." Reverse holds vertical pin. The image is an actual screened b/w photo of the exhibit front. The name appears on the building's front as well as additional text above the huge head of a clown and this reads "The Foolish House." This was one of the most popular attractions 'on the Pike' which was the exposition's amusement area. In addition to the two names we've mentioned it was also known as the Fun Factory. It was noted for screams of laughter issuing from the building and this convinced nearly everyone to spend a dime to investigate the hilarity largely produced by a mirror maze which could trap a victim for many minutes. There was also a collection of cabinets containing various surprises and at the end a circular slide. Celluloid has most trivial trace of stain at far upper left but barely noticeable and the piece displays glossy and Exc. This rare button must have been available only at the fair as it is the only one we've seen and it came from a collection of a person who obviously attended in 1904.