MARCUS THOMAS is a full-time graphic designer, as well as writer and photographer based in Wellington. He has spent a lifetime exploring New Zealand's underworld and been at the forefront of exploration in the longest cave system, Bulmer Cavern. When not adventuring, Marcus spends his time bringing up a family and encouraging them to explore in the outdoors. NEIL SILVERWOOD hails from the West Coast and is a professional photographer specialising in photography of places many would consider too difficult or dangerous. Assignments have been as varied as capturing New Zealand's wildest canyons to skiing in war-torn Afghanistan. Neil regularly shoots for a range of magazines both within New Zealand and around the world including regular contributions to New Zealand Geographic. This project to photograph the diversity of New Zealand's cave systems is his most difficult to date.