Multiparticle production in high energy interactions, from e+e-  annihilation to hadronic
and heavy ion collisions, shows thermal features in species abundances and transverse
momentum spectra, with a universal temperature around 150 - 200 MeV. We propose a common
basis for this behavior. Because of color confinement, the physical vacuum forms an event
horizon for quarks and gluons, which can be crossed only by quantum tunnelling, i.e.,
through the QCD counterpart of Hawking-Unruh radiation. Such radiation cannot transmit
information to the outside; it must be thermal, with a temperature determined by the
strong force at the confinement surface.