The Doctor is an impossible being capable of many impossible things. He is the last of the Time Lords, an advanced alien race from the planet Gallifrey. He travels through time and space in a ship that masquerades as a 1950s British police call box. He saves worlds, hates guns, speaks every language (including baby), and is over 1,100 years old. And instead of dying, he can change regenerate into a new, healthy body, completely different from his last. The transformation is so complete, that even some of his personality traits differ after the process. Regeneration occurs when a Time Lord is about to die, but the energy that drives it can occasionally be accessed at will. Time Lords can regenerate up to 12 times, therefore having the potential to have 13 total incarnations. If a Time Lord so chooses, they can also stop the process from happening and allow themselves to truly die. Almost anything that can kill a normal human can kill a Time Lord. William Hartnell's First Doctor regenerated when his aged body gave out, David Tennant's Tenth Doctor died from radiation exposure, and John Simm's incarnation of the latest Master died from a bullet wound. As we approach the end of Matt Smith's tenure as the Time Lord and welcome Peter Capaldi as the next regeneration, let's take a look back at times when our beloved Doctor managed to survive some fairly impossible things - even for him.