It's Europe's hidden crisis: every month new figures come out showing that there are more young people without work than ever before. More than 5.5m young people are currently kicking their heels on the continent. Revolutions have started with less. What do they do? How do they survive - materially and psychologically. Are they bitter? Is there a feeling that they have trained in the wrong subjects, spent good money on bad degrees? A Guardian project investigates the plight of Europe's youth, finds youngsters who are taking the initiative and seeks practical solutions from those best placed to offer it