CORSIKA (COsmic Ray SImulations for KAscade) is a physics computer software for simulation of extensive air showers induced by high energy cosmic rays, i.e. protons and atomic nuclei, as well as Gamma rays (photons), electrons, and neutrinos. It may be used up to and beyond the highest energies of 100 EeV. It can be used to simulate the generation of Cherenkov radiation, radio emission (Askaryan radiation), and atmospheric neutrinos. A complete rewrite of CORSIKA in C++ named CORSIKA 8 is currently work in progress.