  IceCube detects more than 100,000 neutrinos per year in the GeV- to
PeV-energy range. Among those, we have isolated a flux of high-energy cosmic
neutrinos. I will discuss the instrument, the analysis of the data, the
significance of the discovery of cosmic neutrinos, and the recent
multi-messenger observation of a flaring TeV blazar in coincidence with the
IceCube neutrino alert IC170922.
