  Initial discovery of CRs dates back to a century ago (1912). Their
identification as particles rather than radiation dates to about 20 years later
and in 20 more years also the first suggestion that they were associated with
SNRs was in place. The basic mechanism behind their acceleration was suggested
almost 40 years ago. Much work has been done since then to the aim of proving
that both the acceleration mechanism and site are well understood, but no
definite proof has been obtained: in spite of impressive progress of both
theory and observations, the evidence in support of the commonly accepted
interpretation is only circumstantial. In the following I will try to make the
point on where we stand in terms of how our theories confront with data: I will
review recent progress on the subject and try to point to avenues to pursue in
order to gather new proofs, if not smoking gun evidence of the origin of
Galactic Cosmic Rays.
