There are no computer graphics or digital tricks in these images. Everything that you see happened in real time exactly as you see it.
The recording required 606 takes and in the first 605 takes there always was something, usually of minor importance, that didn't work. It was necessary for the recording team to install the set-up time after time and it took several weeks working day and night to achieve this effect. The recording cost 6 million dollars and it took 3 months to finish.