Simulation representing the second stage of the cosmic reionization, showing the evolution of the hydrogen ionization fronts in the IGM. The volume is (5.3 Mpc)³ in comoving units and contains ten randomly distributed clusters of massive population II/I stars following a Kroupa IMF. The radiation of the clusters is able to reionize the hydrogen content of the simulation volume within the redshift interval from z ~ 10 to z ~ 5.8. (Δt is the time interval since the beginning of the simulation at z = 10).