Centauro-type and Mini-Centauro-type events are reported and discussed. They are events in which nuclear-active particles (i.e. hadrons which do not undergo rapid photon decays) are produced without any sign of accompanying neutral pion emission. Estimated hadron multiplicity is ∠100 for Centauro-type and ∠15 for Mini-Centauro-type.Up to the present moment, 5 examples of Centauro and 13 of Mini-Centauro have been observed in the two-storey emulsion chambers exposed on Mt. Chacaltaya, Bolivia (5220 m above sea level). The experimental results on energy and angular distributions are in agreement with the hypothesis that this type of events occur through production and decay of a fire-ball with a rest energy of (200∠300) GeV/c2 for Centauro and ∠30 GeV/c2 for Mini-Centauro events.