[Cillian] MURPHY: Every day, you had these phenomenal actors, who are heroes of mine, coming in. Every day, you were having to raise your game to work with these legends. Everybody was so unbelievably well-prepared. Every single actor, no matter what size their role or the significance of their character in history, each one of them had this massive depth of knowledge that they could draw on.

[Christopher] NOLAN: I was thinking that it even applied to the extras. We were in the real Los Alamos and we had a lot of real scientists as extras. We needed the crowd of extras to give reactions, and improvise, and we were getting sort of impromptu, very educated speeches. It was really fun to listen to. You’ve been on sets where you’ve got a lot of extras around and they’re more or less thinking about lunch. These guys were thinking about the geopolitical implications of nuclear arms and knew a lot about it. It actually was a great reminder every day of: We have to be really on our game, we have to be faithful to the history here, and really know what we’re up to.

Read the full interview at Entertainment Weekly online.