What kind of admiration should mankind give to birds when they use their wings to realize their dreams and soar in the sky that we can never reach by ourselves? "the migration of birds is a story about commitment, a commitment to return." Jacques Behan took us on a flight of birds and dreams with such a sentence. There is no doubt that the migratory bird directly defines the standard of "getting the truth" of the world's top documentaries-- more than 600 people participated in the shooting, which lasted more than three years and cost more than US $40 million, and the scenery spread over more than 50 countries and regions around the world. the length of the documentary film is more than 460 kilometers. The film, which uses 17 of the world's best pilots and two scientific expedition teams, caused a sensation as soon as it was born. In just three weeks, more than 2.5 million French people walked into the cinema for it, flying over 1200 kilometers of swans' insistence on life, sand dune cranes seeking a way out in the wind and sand, and penguins fighting sea Ravens in the ice and snow. Although there are failures and discouragement, there are wooden brains on the edge of the cliff and peeps from human greed. Except for a simple explanation, there are no words in the whole film. The protagonist of this film is a naive and varied bird. He's...