It's one of the most famous prehistoric monuments in the world. A monument that was first built more than 5,000 years ago. So, its story and use continue to evolve over the following centuries and millennia. And today, it still holds so much meaning to so many people. Stonehenge Now, there are still so many theories surrounding Stonehenge. Its purpose, its construction, its Stone Age significance. And yet, new discoveries continue to reveal more fascinating details. A few years back, for instance, it was revealed that the great sarsen stones that defined Stonehenge, each weighing about 25 to 30 tonnes, came from the Marlborough Downs, roughly 15 miles away. But how exactly these Stone Age people went about transporting those massive blocks remains debated. Living in a world long before written history, it is amazing to think about who these people were, the builders of Stonehenge? How did they view the world around them? What drove them to undertake such a project, to transport these massive stones over 20 kilometres and set them up at Stonehenge? How might they have done it? It's this mysterious world that is the setting for the newest historical novel by one of Britain's most cherished writers, Ken Follett. Now, a few weeks back, I had the pleasure of interviewing Ken all about this novel, Circle of Days, shining a light on the people themselves, the Stone Age men and women who made and used Stonehenge. Welcome to the Ancients. Ken, it is such a pleasure to have you on the show today. Thank you. It's great to be here. And to talk about Circle of Days and Stonehenge for such an iconic monument built more than 4,000 years ago. And the fact that there's still so much mystery surrounding almost every part of the monument, so many theories, is that what makes it such an alluring centrepiece for an epic historical novel? Well, certainly the fact that quite a lot of things are not known leaves the writer of fiction with some room.