Dicke's seminal 1954 paper introduced the notion of  'superradiance' in a system of spins coupled to a common photon mode. Certain quantum states of the spins dominate the radiation process so that the spins radiate coherently. Dicke's original thought experiment has recently been recreated in the lab using cavity-QED setups with two spins. I will explore extending this experiment to N spins and show that the radiation process naturally gives rise to entangled states. This suggests a new experimental tool to create multi-particle entanglement in the lab. In particular, a null-observation (non-observation of emitted photon) can be used to collapse the wavefunction onto a dark state. Remarkably, this dark state has resonating valence bond (RVB) character. We show that the probability of collapse onto the RVB state scales as N ^-1 , making it possible to generate entangled states of more than 20 spins.