  It is shown that recent RHIC data on hadron spectra and elliptic flow can be
excellently reproduced within a hydrodynamic description of the collision
dynamics, and that this provides strong evidence for rapid thermalization while
the system is still in the quark-gluon plasma phase. But even though the
hydrodynamic approach provides an impressive description of the single-particle
momentum distributions, it fails to describe the two-particle momentum
correlation (HBT) data for central Au+Au collisions at RHIC. We suggest that
this is not likely to be repaired by further improvements in our understanding
of the early collision stages, but probably requires a better modelling of the
freeze-out process. We close with a prediction of the phases of the azimuthal
oscillations of the HBT radii in noncentral collisions at RHIC.
