Planet Earth is the most colouful place that we know of, it is a huge part of what makes our home so special. But what is colour? And how has our peception of it shaped the history of our planet. In the first episode Dr Helen Czerski looks at how the earth was transformed from just another dry rock, to the vibrant oasis we see today. She looks at some of the root foundations of colour, including some that we can’t even percieve.