  Cygnus X is a conspicuous massive-star forming region in the Local Arm of the
Galaxy at ~1.4 kpc from the solar system. Gamma-ray observations can be used to
trace cosmic rays (CRs) interacting with the ambient interstellar gas and
low-energy radiation fields. Using the Fermi Large Area Telescope (LAT) we have
discovered the presence of a 50-pc wide cocoon of freshly-accelerated CRs in
the region bounded by the ionization fronts from the young stellar clusters. On
the other hand, the LAT data show that the CR population averaged over the
whole Cygnus complex on a scale of 400 pc is similar to that found in the
interstellar space near the Sun. These results confirm the long-standing
hypothesis that massive star-forming regions host CR factories and shed a new
light on the early phases of CR life in such a turbulent environment.
