Most Chicago architects had very busy offices in the years leading up to the World's Columbian Exposition. Silsbee's was no exception. In addition to being preoccupied with promoting his novel invention, the "moving sidewalk" he was at work on designs for state buildings as well. One of his lesser known, yet possibly his most popular fair exhibit building was a large arena for animal trainer and zoo pioneer Carl Hagenbeck.
Hagenbeck traveled the world to collect animal, archeological and human specimens to be showcased for public display. He became popular for his circuses that traveled the world with trained animals. The World's Columbian Exposition was a perfect place to showcase and market the items and animals that he uncovered in his travels. The arena built for Hagenbeck for his animal and archeological showcase was at the east end of the Midway Plaisance. The show featured animals of every type including performing bears, lions, elephants, parrots and monkeys as well as an array of other exhibited animals. Also on exhibit was an "Ethnological Museum" featuring sculpture, masks, and hunting implements from around of the world.
The arena was 200 feet square and was designed to accommodate 5,000 spectators at a time. In addition to the large arena, the structure featured indoor beer gardens and cafes featuring German wines and food. It was two stories tall and was constructed of iron. Like most of the fair buildings it was covered in staff, which gave it its gleaming white appearance. The building was a Classical Revival structure that featured a symmetrical facade when viewed from the center of the Midway. A central pediment supported by paired columns marked the entry. Below the pediment, was an open cage that had a constant open exhibit of live lions. The facade of the arena was was two-stories tall with broad corner turrets capped with large domes. Like most of the other exposition structures, the Zoological Arena was intended to be temporary and was demolished after the fair.