Blue Division , the Spanish unit of volunteers who left for Russia during the Second World War to fight communism. Villains and heroes for each other , what is certain is that , in the light of history, these soldiers staged some unusual events such as walking 1,000 kilometers in a few weeks for battle . However , we must go back a few years back in history to understand the causes of formation of the Blue Division . It all began with the invasion of the U.R.S.S by Hitler 's Nazi Germany . The mobilization