Propelled by a unique biodiesel produced from leftover chocolates, this vehicle arrived in Mali's central city Timbuktu on December 22. Nicknamed BioTruck, the vehicle started its journey from the UK on November 26. The BioTruck team claims this is the world's first carbon-negative driving expedition across the Sahara desert. The expedition was to raise public awareness about biofuels and their potential to ease the impact of climate change, as well as to explore the value of different carbon-reducing measures.