  We present the first 3-dimensional high resolution hydro-dynamical
simulations of the interaction between the hot ionised intra-cluster medium and
the cold interstellar medium of spiral galaxies. Ram pressure and
turbulent/viscous stripping removes 100% of the atomic hydrogen content of
luminous galaxies like the Milky Way within 100 million years. These mechanisms
naturally account for the morphology of S0 galaxies, the rapid truncation of
star formation implied by spectroscopic observations, as well as a host of
observational data on the HI morphology of galaxies in clusters.
