The paper summarizes recent advances in physics of multiple-mirror confinement. GOL-3 in Novosibirsk is the only existing large-scale device of this type. Achieved plasma parameters are: n ~ 1021 m-3, T ~ 2 keV, E ~ 1 ms. Intense experimental and theoretical studies revealed several new collective phenomena that radically change plasma behavior in the trap as compared to simple classical theory. These phenomena are intrinsically linked to the second major feature of GOL-3, namely, fast plasma heating by a high-power relativistic electron beam. Collective beam-plasma interaction delivers energy to plasma through strong Langmuir turbulence and changes other plasma properties as well. In particular, the turbulent plasma in GOL-3 features suppressed axial heat transport, fast collective heating of ions, limitation of axial particle loss, and MHD stabilization by a magnetic shear. Mentioned phenomena greatly improve prospects of multiple-mirror confinement for fusion reactor applications. An outlook for possible fusion-scale device is presented.