There is a theory that scientists once dismissed as absurd - that long ago the Earth became so cold every inch of it was entombed in ice. The whole planet became one vast snowball lasting for ten million years. Naked Science probes this controversial theory, looking at the proof of global glaciations in the hot, dry deserts of South Australia. We investigate the theories of how our planet entered this deep freeze and how life could have survived this global catastrophe and what caused it to end? Some even suggest that Snowball Earth brought about the evolution of multi-cellular life form and we look at what would happen to our lives if the ice was to return.