Mars, Venus, Mercury and Jupiter have all been visited by spacecraft. For the first time scientists have seen in sharp detail the continents, mountains, valleys and volcanoes of other worlds. But tonight's programme is more than a story of exploration. It shows how these geological features give clues to the way the planets evolved; how they have helped scientists in their attempt to reach back 5,000-million years to understand the formation of the solar system itself.

"...not a single minute of the programme less than fascinating." (The Times)