left: Speaker Dr. Paul MacCready’s company, AeroVironment, developed a lightweight, 247-foot solar-powered plane, Helios, that flew over Hawaii and reached an altitude of 96,863 feet. right: Speaker John Stossel, co-host of 20/20, on the cover of his bestselling book.

Jerry Andrus

This visionary, magician, and skeptic is the world’s greatest inventor of optical illusions. Andrus will set up his equipment so you can experience and enjoy some of the bizarre quirks of visual perception.