Sci-Fi is a genre that, until recently, was far more advanced than film-makers' capabilities.
The technologically advanced civilisations, the superpowers, and the post-apocalyptic are all things that have previously been difficult to do the visual justice they deserve.
So, right up until visual effects reached their current computer-powered capabilities, the easiest way for these things to be represented properly on screen convincingly was to draw them.
It might sound simplistic, especially when you consider the sheer timeless beauty of some of the entries on this list, but sci-fi is a genre that really highlights what an art form animation is.
Sci-Fi isn't always a genre that's particularly child-friendly, but once you add some colourful animation it's surprising just how easy it is to repackage a sci-fi movie into something that children will treasure and look back on with extreme nostalgia.
There are so many brilliant animated science fiction movies, many of them adaptations of existing movie franchises, and some adaptations of manga or comic books, and it's difficult to pick out just 10 that deserve the title "the best", but here they are.