  We study the correlated spontaneous emission from a dense spherical cloud of
N atoms uniformly excited by absorption of a single photon. We find that the
decay of such a state depends on the relation between an effective Rabi
frequency Omega, which is proportional to sqrt{N}, and the time of photon
flight through the cloud R/c. If Omega*R/c < 1 the state exponentially decays
with rate Omega^{2}*R/c and the state life time is greater then R/c. In the
opposite limit Omega*R/c >> 1, the coupled atom-radiation system oscillates
between the collective Dicke state (with no-photons) and the atomic ground
state (with one photon) with frequency Omega while decaying at a rate c/R.
