In this 1989 CNN interview, Ted Turner interviews Carl Sagan on the environment, nuclear warfare, space, time travel, SETI, and other topics. Turner frequently seems to be out of his depth during this interview (as in part four, when he suggests that time travel to "live with the Indians" might be a good solution for modern-day environmental problems). Regardless, this is an interesting discussion, largely because of Sagan's calm, intelligent discourse. According to Wikipedia, this was supposed to be the fourteenth episode of Cosmos:

Some versions of the series including the first North American home video release included a specially made 14th episode, which consisted of an hour-long interview between Sagan and Ted Turner, in which the two discussed the series and new discoveries in the years since its first broadcast. This unique episode was not included in the DVD release.

So tonight, sit back and watch what was supposed to be the final installment of Cosmos -- albeit many years after the original, and without any of the wonderful production and theatricality of the original series.

Part 1 - Nuclear Weapons

While other topics are discussed, this is primarily about nuclear weapons and deterrence.

Sagan: "The professed function of the nuclear weapons on each side is to prevent the other side from using their nuclear weapons. If that's all it is, then we've gotta ask: how many nuclear weapons do you need to do that? ... You probably don't need more weapons than what's required to destroy every city on earth. There's only 2,300 cities. So, the United States, by that criteria, only needs 2,300 nuclear weapons -- well, we've got more than 25,000!"

Turner: "But not all those cities are our enemies!"

Sagan: "Of course not! A lot of those are our own cities!"

Part 2 - Nuclear Winter and the Environment

Turner: "Could you bring us up-to-date on [nuclear winter]?"

Sagan: (some minutes later) "We're in very bad trouble if we don't understand the planet we're trying to save."

Part 3 - Space & Time Travel

Sagan: "No other planet in the solar system is a suitable home for human beings; it's this world or nothing. That's a very powerful perception."

Turner: (some minutes later) "Are you a Socialist?"

Part 4 - The Environment, Time Travel, SETI, & Education

Turner: "If the world is gonna be environmentally degraded, you could take a few friends of yours and we could go back in the past and try and see if we couldn't live with the Indians a couple hundred years ago, before the white man came."

Sagan: "The trouble is that to do that, you need such an advanced technology that -- with that technology, you could solve our problem, or at least solve us. We might be more the problem than the technology."

Part 5 - Where Did We Come From, SDI, & Politics

Sagan: "I would love to believe that there was a God who made us, who's looking out for us, who's taking care of us, because we're in such a mess. [...] Then we would be relieved of the responsibility of taking care of ourselves. [...] But that does not seem to be the case; we have to solve our own problems."