  A simple physical realization of an integer quantum Hall state of interacting
two dimensional bosons is provided. This is an example of a "symmetry-protected
topological" (SPT) phase which is a generalization of the concept of
topological insulators to systems of interacting bosons or fermions. Universal
physical properties of the boson integer quantum Hall state are described and
shown to correspond to those expected from general classifications of SPT
phases.
