  Kinematical and morphological features observed in early-type galaxies
provide valuable insights into the evolution of their hosts. We studied the
origin of prolate rotation (i.e., rotation around the long axis) in Illustris
large-scale cosmological hydrodynamical simulations. We found that basically
all the simulated massive prolate rotators were created in relatively recent
major mergers of galaxies. Such mergers are expected to produce tidal features
such as tails, shells, asymmetric stellar halos. We investigated deep optical
images of prolate rotators, including newly obtained Milankovi\'c data,
revealing signs of galaxy interaction in all of them. This correlation proves
to be statistically very significant when compared with a general sample of
early-type galaxies from the MATLAS deep imaging survey. In an ongoing project,
we use Milankovi\'c to assemble deep images of the complete sample of all known
nearby massive prolate rotators. Additionally, we searched these data for
asteroids to improve the accuracy of trajectories and even discover one
previously unknown main-belt asteroid. The most frequent tidal features among
the prolate rotators happen to be shells. We developed methods to calculate the
probable time of the merger from optical images. This will allow us to compare
the merger history of the sample with predictions from Illustris. Our plan is
to expand these methods to even larger samples of shell galaxies supplied by
upcoming large surveys like LSST at Rubin Observatory. This will provide an
unprecedented amount of statistically significant data on the recent merger
history of our Universe and allow extensive investigation of the impact of
mergers to a wide range of other astrophysical phenomena.
