The soundtrack for this documentary was performed by the Moscow Symphony, and recorded in Moscow. Oddly, this allowed people to view the previously classified material that the former USSR, now Russia, wanted and tried hard to procure it.
One of the goals of this film, put together by noted special effects man Peter Kuran (the "Star Wars" films), was to restore and preserve the actual films of the atomic bomb tests which were being neglected by the government and were deteriorating.
Some of the footage used in this documentary is from another documentary, "Tsar Bomba." This footage deals with a 60,000 pound device that is called in this film the Soviet's "monster bomb." When it was tested, it created the largest explosion ever created by man.
Color restoration of archive footage was done "via a process called Restored Color Image, a photo-chemical process that restores an old color film negative to its original scheme." (Variety review)