Doctor Who stories

As a centuries-old time traveler, the Doctor has lost more than one companion over the course of Doctor Who's soon-to-be 50-year run. While most departures became a blip on the Doctor's radar (companions DO come and go), sometimes they happened to be totally heart-wrenching for our beloved Time Lord, as in the recent cases of Rose Tyler (Billie Piper) and Donna Noble (Catherine Tate).