The Sunsphere is a 266-foot high hexagonal steel truss structure, topped with a 74-foot bronze glass-plated sphere. It is the most distinctive structure on the Knoxville, Tennessee skyline.

The Sunsphere was created as the theme structure for the 1982 World's Fair. While the fair itself was regarded as a failure, the Sunsphere was noted for its unique design in several engineering publications. Today, most of the World's Fair Park surrounding the sphere has been replaced by a University of Tennessee parking garage and a convention center, but the Sunsphere itself shows no sign of going away.

However, to most people (including residents of East Tennessee), the Sunsphere is more frequently "appreciated" for its eccentricity and uselessness than its unique design. University of Tennessee students (the university is adjacent to the former World's Fair site) have occasionally held competitions for "alternate uses" of the Sunsphere, and even the popular television show The Simpsons got in the act once, as Bart accidentally topples the object (which, in The Simpsons universe, has become a center for wig outlets) during one episode which pays ironic tribute to the 1982 World's Fair.