To close this year's Superquark series, a very special BBC documentary on the polar bear. Cameras hidden in icebergs, snowballs and more have spied on the life of bears in such a difficult environment and their ability to adapt to the world of ice. Beautiful and funny images. In May 1942, 19 Royal Air Force bombers carried out a very high-risk mission, which cost the lives of 56 English airmen and the loss of eight aircraft. The purpose of the mission: to destroy the dams of the Ruhr mining region, to weaken German production capacity. Alberto Angela retraces the stages of this little-known event of the Second World War. Super megacities with over 25 million inhabitants seem to be the trademark of this century. In 2025, China will have 15 cities with a similar population.