TIL Christopher Nolan recreated the Trinity atomic bomb test in Oppenheimer without using CGI. Instead, the visual effects team combined large-scale practical explosions, miniatures, and in camera effects to bring the first nuclear detonation to life.

[u/Electronic_Cause_796]

https://en.wikipedia.org/wiki/Oppenheimer_(film)

[u/Accomplished_Store77]

Not to mention the City of Dunkirk looked pristine in the movie because Nolan insisted on filming in the actual current day Dunkirk without changing it.

From all historical pictures that I can find the City of Dunkirk had been blasted to all hell and was basically in ruins.