One step at a time, scientists are reconstructing the tree of life. Gaps in our knowledge are closing. However, numerous questions still remain unanswered. For example, why do we need to sleep? What is intelligence? And which language do animals speak? In the third part of the series, we look for answers to the great mysteries of evolution. We travel with animals and try to fathom the future of evolution. Genetic scientist George Church from the Harvard Medical School is one of the people who are helping to shape this future. Using new tools from the gene laboratory, he wants to wipe out diseases and bring back to life extinct species like the mammoth. Can his plan work? And do we really want it to?