DNA is celebrated as the molecule that carries our genes from generation to generation. But a small group of pioneering chemists and physcists are using DNA to build the nano-engines of the future. Quentin Cooper hears about these miniature biological machines. The Nazca civilisation is famous for the giant lines it inscribed into the high Peruvian desert; catastrophic deforestation is now blamed for its demise 1500 years ago. ESA's SMOS satellite is intended to map soil moisture across the planet and the trajectories of the ocean currents. Quentin hears how it will improve weather forecasts.