Exploring QCD phase diagram in Heavy Ion Collisions

Based on the recent findings of Lattice Gauge Theory and effective models we introduce the phase structure of strongly interacting matter at finite temperature and density. We discuss, how the transition from hadronic phase to a quark gluon plasma can be explored experimentally in heavy ion collisions. In particular, we show that by measuring fluctuations of conserved charges one can probe remnants of the chiral phase transition, whereas yields of charmonia can provide a direct access to the deconfinement transition in QCD medium. The theoretical expectations will be contrasted with recent data obtained in heavy ion collisions at LHC and RHIC energies by ALICE experiment at CERN and STAR experiment at BNL, respectively.