While uncredited, Billy Curtis played Tiny Allen the midget. Also known for Wizard of Oz and High Plains Drifter with Clint Eastwood.
The title is from the slogan from the Ringling Brothers and Barnum Bailey Circus - "The Greatest Show on Earth!"
The name of the circus is Farnum and Daley, a name patterned after the real-life circus Barnum and Bailey.
When Raymond throws knives into Hondo's biceps, square pieces of protective padding can be seen under Hondo's leotard.