Circus World Museum is the world's largest historical attraction pertaining to the circus. The 50-acre complex is located at the Ringling Bros. Circus original winter quarters - a national historic landmark. Each year nearly 200,000 visitors tour the unique museum.
There is a wonderful short film on the history of the circus in the United States. Also, the picture gallery and cart museum are great to check out. During the summer months they have a small circus on site that you can attend. Lots of fun for the whole family.
http://www.circusworldmuseum.com/