The search for the origin of high-energy cosmic rays has made significant progress in the past decade. By including multi-messenger methods, the general picture of the presence of a galactic component at low energies and an extragalactic one at the highest energies has been strengthened. Yet, unambiguous proof of the exact origins of cosmic rays is still missing. This chapter will review localized regions in the galaxy, which, due to their high nonthermal emission, are likely cosmic ray cradles. What we can learn from combining theoretical modeling with multi-messenger observations of regions like the Cygnus X complex, the Eta Carinae, and the Galactic Center region will be discussed. How the investigation of such localized regions in the Milky Way will help to resolve the more than 100-year-old question: what is the origin of cosmic rays? will be reviewed.
Part of the book: Cosmic Rays