Gamma Rays from Violent Interstellar Events

As an illustration of what the next generation of γ-ray telescopes may show us, an up-to-date COS-B `finding chart' of potential γ-ray point sources and unexplained extended γ-ray features is presented. The latter, in particular, may be related to energetic phenomena in the interstellar medium, capable of enhancing the local cosmic-ray density. As an example, a prominent feature, extending over at least 10° - 15° almost perpendicular to the Galactic disk, is discussed in some detail, linking it to the giant HII region S54 and Complex C of high-velocity clouds.