UFOs, demons, tornadoes, hedgehogs and Mother Earth herself have all been identified as the force behind crop circles, but the reality is perhaps more incredible. The formations are made by ordinary people, working through the night in small teams, usually equipped with nothing more than planks of wood, rope and tape measures. For the first time, the team behind some of the most spectacular crop circles of the past 20 years, whose work has appeared all across the UK, the USA, New Zealand and Continental Europe, reveal their secrets.