Fan theories: where would Doctor Who be without them? Well, there'd be far fewer pictures on the internet of Peter Capaldi kissing Matt Lucas, that's for sure.
When a show is as popular and successful as Doctor Who, fan theories and speculation are never in short supply. Sometimes, these theories are completely outlandish, and would never actually work in the reality of the show. Either that, or we just don't like them. But we aren't going to name and shame here.
Other times though, fans come up with ideas so brilliant that they put what actually happened to shame.
So, we've scoured the web for some theories like this (mainly making use of our good pals over at Reddit). These theories all improve on existing Doctor Who stories, or, in some cases, create entirely new ones that we would've enjoyed far more.
The great thing about Doctor Who is that we could even consider these theories alternate timelines or parallel worlds if we wanted to. Heck, if Dimensions in Time can happen, then these things can too!
10. The Lupari Are From Barcelona
Let's start with a silly one.
The Lupari were introduced in Flux as the dog-faced protectors of the human race. No, literally, they had the faces of dogs. That wasn't an insult.
While it's revealed that the Lupari have sworn to protect humanity, their exact origins are never revealed. Enter this incredible fan theory that references the final episode of the very first series of NuWho.
As the Ninth Doctor is about to regenerate, he asks Rose if she wants to visit Barcelona. Not the city of Barcelona, but the planet of Barcelona. He remarks that the world is home to "dogs with no noses", before laughing about how many times they must hear that joke.
The presence of alien dogs clearly got one Reddit user thinking, who suggested that those noseless hounds were early ancestors of the Lupari. Barcelona (the football team) was even mentioned in The Halloween Apocalypse, the episode which introduced Karvanista, a member of the Lupari race.
This revelation wouldn't have changed anything major, but it would've been a nice nod back to the early days of Doctor Who's revival.