16. Bad Wolf/The Parting Of The Ways (Ninth Doctor)
In the 1964 story The Dalek Invasion Of Earth, we got to see what a full-fledged invasion from the Daleks looked like. In 2005, we got to see it again, better than ever before, and better than we've seen since. Despite the impressive updated effects, despite the vast amounts of Dalek ships, despite anything else, the impact of this entire story can be boiled down to one scene... The Doctor's companion Rose Tyler has been captured by the Daleks. He manages to open a channel of communication with them, and this is what follows: https://www.youtube.com/watch?v=oYoLG_iP9Ec
15. Silence In The Library/Forest Of The Dead (Tenth Doctor)
In this two-parter from 2008, the Doctor takes Donna Noble to a planet wide library. Because why not? Upon arrival, they learn that everybody is gone. No trace of anyone, no sign of struggle or foul play. Just everybody gone. In fact, there are three distinct plotlines in this epic story. The mystery of everyone's disappearance, a little girl who is somehow picking them up on her television, and a mysterious woman named River Song who knows more about the Doctor than anyone else alive. This story also introduced the Vashta Nerada, airborne piranha-like species who lurk in the shadows, and somehow have yet to make another appearance.