From frigid canyons kilometres deep, to sprouting geysers that reach space, we embark on a grand tour of the solar system, unravelling the secrets that the planets have harboured for millions of years and discovering that Earth came close to almost not existing at all.

We have been mesmerized by Venus since ancient times. Was this a paradise world teeming with life? This film tells the remarkable story of how spacecraft revealed the true nature of Earth's enigmatic twin, that it's a lifeless hell – and that the Earth could follow suit.