What is the 100th episode of Doctor Who called?

Answer 1

The short answer is "An Unearthly Child".

The longer answer is; back then, like now, every individual episode had it's own title, but unlike now, all the stories (bar one) were serialised into a number of parts. It is generally regarded that the first story was a four part tale, consisting of the episodes "An Unearthly Child", "The Cave of Skulls", "The Forest of Fear" and "The Firemaker". However, as the first episode takes place in London in 1963, while the other 3 take place on prehistoric Earth, some (very few) people claim that the first "story" was the single part "An Unearthly Child", and the second "story" was the three part "100,000 BC". A larger contingent of fans prefer to encapsulate all 4 of these episodes under the umbrella title "100,000 BC". A very small number also name either all 4 episodes or the final 3 as "The Tribe of Gum", with respect to the tribe encountered by the Doctor and his companions in those final 3 episodes.

The Novelisation, published by target in 1981 was titled "An Unearthly Child", covered all 4 episodes, but does not end the argument, as many Target novelisations did not share titles with the serials that they were based on (eg "Terror of the Zygons" vs "Doctor Who and the Loch Ness Monster" and "Frontier in Space" vs "Doctor Who and the Space War" etc. Neither does the fact that all 4 episodes were covered by the book end the argument over whether this is 2 stories (a 1 part and a 3 part) or a single (4 part story), as the 12 part epic "The Dalek's Master Plan" was not only split into 2 books ("Mission to the Unknown" and "The Mutation of Time"), but the first book also covered an episode "Mission to the Unknown", which is the only TV episode not to feature the Doctor, the TARDIS, or any of the original cast, but sets up the events of "The Dalek's Master Plan". It is regarded as a separate story, as it was broadcast a whole month before the first episode of "Master Plan", being separated by 4 part story "The Myth Makers".

Both the VHS and DVD releases (1990 and 2006 respectively) were titled "An Unearthly Child". The DVD was bundled with 7 part "The Daleks" (aka "The Mutants" - but let's not go there) and the 2 part story "The Edge of Destruction" (aka "Inside the Spaceship" - let's not go there either!) under the umbrella title "The Beginning", as these were the first three Doctor Who stories.

I'm sure this gives you MUCH more information than you actually wanted, but I'd rather give too much than too little. :-) When I initially composed this answer, I hadn't given the answer "An Unearthly Child" until halfway through the first paragraph. I'm sure you're grateful for the re-write!

Answer 2

The 100th story or serial of Doctor Who is the Stones of Blood.

The 100th individual episode is called Escape Switch, which is the 10th episode of the serial The Daleks' Master Plan