World's Biggest Bomb (2011, Documentary)

Beginning in the 1950s, American and Soviet scientists embarked on a perilous race to see who could build and detonate the world’s largest bomb. The results exceeded all expectations about how big a bomb could be built. Initially, the Americans led the way, but then left the field clear for the Soviet Union to break all records.
Secrets of the Dead chronicles how the bomb-makers on both sides were working blind as they pushed science into unknown territory to build The World’s Biggest Bomb. As we approach the 50th anniversary of the detonation of the most powerful bomb ever constructed – October 30, 1961.

Alex4History's supplementary notes:
From the Secrets of the Dead series
Narrated by: Liev Schreiber