Doctor Who: 20 Things You Didn’t Know About A Christmas Carol
5. Everything’s Round For A Reason
"What are the round things?" Well, in this episode, they're everything.
Sardicktown isn't just special because Michael Gambon and Katherine Jenkins live there, it's special because the human inhabitants share their world with shoals of floating fish.
As well as Clive the Shark, there are smaller fishies dotted around the town, gathering round lampposts and swimming through the sky. This gave the production team an interesting job – to create a world that felt right for both humans and their flying friends.
The answer? Round things.
Almost all of the windows, light fittings, and even some of the buildings in Sardicktown are circular or semi-circular. Rather than lazy production design, this was done on purpose to evoke the feeling of being in a submarine, one of the closest experiences human beings can get to living underwater.
Next time you watch A Christmas Carol, you won't be able to unsee this.