The largest Arctic Expedition ever - MOSAiC has started. It could be the largest-scale Arctic research expedition of all time: On 20th of September 2019 the German research icebreaker Polarstern departed from Tromsø, Norway and, once it had reached its destination, will spend the next year drifting through the Arctic Ocean, trapped in the ice. A total of 600 people from 19 countries, who will be supplied by other icebreakers and aircraft, will participate in the expedition – and several times that number of researchers will subsequently use the data gathered to take climate and ecosystem research to the next level. The mission will be spearheaded by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI).