Rather than relying on CGI to bring Nolan's vision to life, the team used FX shots by combining live action with digital animation, visual effects supervisor Paul Franklin told Wired.
Visually stunning moments like the city of Paris folding over itself and Arthur fighting projections in a zero-gravity rotating hallway were shot using visual effects.
"Using CG versions of complicated action like falling buildings, explosions or certain lighting effects are all predetermined by the nature of the software and the ideas that went into it. In the effects world, there's still a lot of useful randomness in real-world physics," Franklin explained.
The limbo scene, with large buildings falling apart on the beach, was the most difficult scene to create, according to Franklin.
"For a long time we just couldn't get it right – we'd end up with something that looked like an iceberg version of Gotham City with water running through it," he said.
They based the model off of a glacier, and a designer filled in the gaps with the architecture seen in the movie.
"It was just a matter of methodically adding in elements like roads, intersections, and ravines until we ended up with this extremely complicated (but organic-looking) cityscape," Franklin explained.