Various kinds of migrating birds, includingcranes, arrive in Japanat the beginningof winter and fly away uponthe arrival of springs. But from where do they come, and to where are they destined? Long a guessing game, the puzzle of these beautiful birds has finaly been solved. Using specially developed transmitters, a weather satellite, and the equipment of the Toulouse Space Center, we trace the extraordinary journey of a family of cranes over 5,000 kilometers. From southern Japan, through the Korean Peninsula, then on to China and Russia, their trip reveals an important aspect of the behavior of cranes never previously documented.