  The collective phenomena are observed not only in heavy ion collisions, but
also in the proton-nucleus and in high-multiplicity $pp$ collisions. The latest
results from this area obtained in ATLAS are presented. In $p$+Pb collisions
the emission source of particles is measured using the HBT method. The analysis
of $p$+Pb data collected in 2016 provides information on the elliptic flow of
charged hadrons and muons. Low multiplicity events from $pp$, $p$+Pb and
peripheral Pb+Pb collisions are studied with the cumulant methods. A deeper
understanding of Pb+Pb collisions is provided by the analysis of longitudinal
fluctuations of the collective flow parameters.
