10 entrepreneurs who changed the world

Turner took over Turner Advertising Co. at 24 after his father's death and later went on to found CNN, the world's first 24-hour cable news channel. Turner said that making a news channel that was constantly broadcasting seemed like the most obvious move in the world to him. "It really doesn't cost that much more to do twenty-four hours of news than it does two-and-a-half hours of news," Turner said. "You've got to have the news gathering organization.... I was going to have to hit hard and move incredibly fast. And that's what we did: moved so fast that the networks wouldn't have time to respond, because they should have done this, not me, but they didn't have any imagination, or didn't have adequate imagination."