Cars are central to the hustle and bustle of modern city life but they're also contributing to 20 percent of all greenhouse gas emissions. If global warming targets are to be met, decarbonizing vehicles is an urgent priority. To help find a solution, 500 engineering students from 28 different countries met at a unique race near London, designed to help find the low-emission cars of the future. 

In the Shell Eco Marathon, student engineers and innovators compete against each other to design, build and race the energy-efficient cars of the future. They're building what are essentially prototypes of next-generation cleaner cars, powered by traditional diesel and gasoline as well as lower-carbon electric and hydrogen technologies. Their goal is to achieve one thing: the greatest distance on just one liter of fuel or one kilowatt of electricity.