  We study three dimensional systems where strong repulsion leads to an
insulating state via spontaneously generated spin-orbit interactions. We
discuss a microscopic model where the resulting state is topological. Such
topological `Mott' insulators differ from their band insulator counterparts in
that they possess an additional order parameter, a rotation matrix, that
describes the spontaneous breaking of spin-rotation symmetry. We show that line
defects of this order are associated with protected one dimensional modes in
the {\em strong} topological Mott insulator, which provides a bulk
characterization of this phase.
