From the wireless to the computer, and from hula hoops to interplanetary travel, inventions and discoveries have changed our lifestyles in ways that would have astounded our ancestors. Each of them was originally developed by visionaries who dreamt of the seemingly impossible, but who were opposed by an array of experts publicly declaring that ‘It cannot be done.’ Well, yes it could . . . And here's the story of how those dreamers overcame the odds against them.