  We show that a consistent hydrodynamic description of soft-hadronic one- and
two-particle observables (the HBT radii) studied in the relativistic heavy-ion
collisions at RHIC may be obtained if one uses the Gaussian energy density
profile as the initial condition. The transverse-momentum spectra, the elliptic
flow coefficient $v_2$, and the pionic azimuthally sensitive HBT radii are
successfully reproduced, which hints that the long standing HBT puzzle has been
solved.
