  In nucleus-nucleus collisions at relativistic energies a new kind of matter
is created, the Quark-Gluon Plasma (QGP). The phase diagram of such matter and
the chemical freeze-out points will be presented in connection to the
pseudo-critical temperature for the chiral cross over transition. The role of
conserved charge fluctuations to give experimental access to the nature of the
chiral phase transition will be summarized in terms of the relation to lattice
QCD and the current experimental data. The QGP can be characterized as a nearly
ideal liquid expanding hydrodynamically and the experimental data allow to
extract transport parameters such as the bulk and shear viscosities. The energy
loss of partons in the QGP probes the high parton density of the medium. The
role of quarkonia and open charm hadrons as a probe of deconfinement and
hadronization form the final topic.
