  We discuss predictions for the pion and kaon interferometry measurements in
relativistic heavy ion collisions at SPS and RHIC energies. In particular, we
confront relativistic transport model calculations that include explicitly a
first-order phase transition from a thermalized quark-gluon plasma to a hadron
gas with recent data from the RHIC experiments. We critically examine the
"HBT-puzzle" both from the theoretical as well as from the experimental point
of view. Alternative scenarios are briefly explained.
