Avatar: The Way of Water producer Jon Landau opens up about which scene in the film was the hardest to shoot. As a movie taking place on the distant planet of Pandora, Avatar: The Way of Water features a new world filled with alien plants, animals, and people. As humanity continues to try to mine the planet's resources, the Na'Vi have to take yet another stand against the humans, and it means turning to Pandora's seas for defense.

While Avatar: The Way of Water's underwater scenes are incredible, they were painfully difficult to film. Countless hours of work went into designing the underwater world, and it made Avatar: The Way of Water a serious challenge for the cast and crew. In an interview with The Hollywood Reporter, Landau was asked about which film was the toughest — and most rewarding — to shoot, and he easily found an answer. Check out his quote below:

I’ll talk about the scene that we call 'the first swim.' It’s when the kids jump into the water for the first time and we’re taking an audience into that environment. [We would] go back to references that we had shot of performers in the Bahamas and references we had done in the performance-capture tank. We’re in a realm where audiences know what’s real. If you are in an inferno and there’s fire everywhere and people are walking through it and not being affected, nobody can relate to that. But everybody has seen footage of people jumping [into water], many people have done it themselves. We shot references of all the costumes underwater and how they moved to make sure that it was authentic when Weta FX started coming back with their simulations. There is a moment of wonder on Kiri’s face — it’s a moment that I loved, where she reaches out and she’s touching things underwater. That is based on an experience that we all did together as part of the training for The Way of Water, where we went to Hawaii for a sense-memory experience for the cast. We did it on the first movie, but we only did it in the rain forest, and for this movie we did it in the rain forest and in the oceans. We took the cast diving underwater on a night scuba dive. In the darkness of the ocean, 30 feet down, we did perhaps the most Pandoran-like thing one could do on Earth: We saw giant manta rays come out of the darkness and swim over us. Sigourney was able to reach her hand out and touch one of their bellies. That is the sense of wonder she then conveyed to an audience with her performance in that first swim sequence.

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Why Avatar 2's Underwater Scenes Were So Hard To Film

Swimming with jellyfish in Avatar: The Way of Water

It was an absolute pain to shoot even the above-sea-level scenes, thanks to having to use CGI on nearly every shot. Yet the underwater scenes added an extra layer of difficulty for the Avatar: The Way of Water VFX team. Both the cast and the crew needed to adapt for filming by adjusting make-up, costumes, sets, and by adding to the actors' skill sets.

In order to adjust to the underwater world, Avatar: The Way of Water star Sigourney Weaver revealed having trained with Navy SEAL instructors just to ensure that she could actually shoot the movie. Long underwater scenes meant that the actors needed to hold their breath for so long that Kate Winslet even broke Tom Cruise's record by remaining underwater for seven straight minutes. Every scene also needed to be shot in motion-capture suits, meaning that actors were unable to breathe, dressed in limiting clothing, and had to emote all at the same time.

The effort eventually proved to have paid off upon release as the final effects on Avatar: The Way of Water have been hailed as just as stunning as the original. The world of Pandora still feels realistic, despite having been largely created out of CGI elements and VFX work. While it was a physically demanding shoot that required actors to learn how to dive without protecting equipment, Avatar: The Way of Water proved that no setting is truly beyond Hollywood's technological capabilities, especially as the franchise continues to grow.

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