The idea of regeneration is built into Doctor Who’s DNA, so it’s fitting that it was successfully revived after a long period of inactivity. The Doctor first began his time-traveling adventures in 1963, and the series ran for 26 years (and through seven Time Lords) before getting exterminated by the BBC in 1989. Aside from a few books and a made-for-TV movie starring Paul McCann (Withnail and I), the Doctor lay dormant for the better part of 15 years. But then, in 2001, the character was resurrected in a few hugely popular webisodes, renewing interest in the show. Whovians rejoiced when, in 2005, the series was rebooted for good, with Christopher Eccleston stepping into the Doctor’s shoes; it's since had an arguably more successful run than before, with three actors taking on the Time Lord role (the latest, Peter Capaldi, officially begins his tenure in August), and its fandom bigger and more fervent than ever.