Cosmic Rays (CRs) were discovered over a century ago, but their origin is still unclear. CRs with energy up to a few PeV are generally believed to be produced in the galaxy, whereas CRs above a few EeV are considered extra-galactic. Supernova remnants are widely considered the potential sources of galactic cosmic rays, while Active Galactic Nuclei and gamma-ray bursts are potential sources of CRs at the highest energies. However, no clear evidence has emerged from recent astronomical observations in favor of the standard scenarios of cosmic ray sources against the expectations. Here, we shall briefly review the standard model of the origin of CRs and critically analyze the present status of the model in light of recent observations from very high-energy gamma-ray and neutrino astronomy.