Coupling between inertial particles and a carrier phase may lead to strong spatial segregation from an initially homogeneous system. In the presence of gravity and at sufficient mass loading, dense clusters of particles form that control the underlying fluid turbulence. This movie shows fully-developed cluster-induced turbulence, where all production in fluid-phase turbulent kinetic energy arises due to momentum coupling between the phases. Particle position is shown on the left, while instantaneous granular temperature is shown on the right.