MARS is Monte Carlo code for inclusive and exclusive simulation of three-dimensional hadronic and electromagnetic cascades, muon, heavy-ion and low-energy neutron transport in accelerator, detector and shielding components. Examples of radiation assessment are shown for several projects such as ILC main linac, Fermilab Booster, LBNF, Femilab Recycler and Higgs Factory. New option for geometry description is demonstrated. Applicability of MARS for current ESS needs are discussed.