  By now there is substantial evidence that Gamma-Ray Bursts (GRBs) originate
at cosmological distances from very powerful explosions. The interaction
between a GRB and its surrounding environment has dramatic consequences on the
environment itself. At early times, the strong X-ray UV afterglow flux
photoionizes the medium on distance scales on the order of 100 pc or more. Here
I discuss the long-term effects resulting from the interaction between a GRB
and its environment, and in particular the signatures of the emission spectrum
produced while the heated and ionized gas slowly cools and recombines. Besides
photoionizing the medium with its afterglow, a GRB explosion drives a blast
wave which is expected to have a very long lifetime. I discuss possible
candidates for such GRB remnants in our own and in nearby galaxies, and ways to
distinguish them from remnants due to other phenomena, such as multiple
supernova (SN) explosions.
