Back in the 60's, the BBC would reuse broadcast video tapes to save on costs — a practice that resulted in more than 100 lost episodes of Doctor Who, 106 of which still haven't been found. Now two of those episodes have been recovered from a fan of the show and broadcast engineer, Terry Burnett, who had purchased film copies originally made for international broadcast. The recovered recordings feature William Hartnell and Patrick Troughton, the first two actors to ever play The Doctor — one is "Airlock," the third episode in a 1965 story called Galaxy 4, and the other is the second episode of an extended story called Underwater Menace from 1967. Doctor Who is the longest running science fiction TV series in the world, and you can watch clips from the two recently-returned prodigals online.