A Russian state corporation has released previously-classified footage documenting the development and detonation of the legendary 'Tsar Bomba' hydrogen bomb in celebration of 75 years of Russia's nuclear industry.

The footage, which comes during a 40-minute Soviet-style propaganda film, was released on the YouTube channel of the Rosatom State Atomic Energy Corporation, the state-run Russian nuclear energy concern, on Aug. 20. 

The film details the long march of the Tsar Bomba — the informal name given to the RDS-220 hydrogen bomb by Western observers of the Soviet Union — from its transport by steam train to Olenya Air Base in northwest Russia to its final detonation above Novaya Zemlya on Oct. 30, 1961.

More importantly, it provides never-before-seen shots of the actual Tsar Bomba explosion, which had an estimated yield of around 50 megatons, or 50 million tons of TNT, in exquisite detail compared to previously-released footage of the detonation. 

Russia just released classified footage of the largest nuclear bomb detonation in history
Russia just released classified footage of the largest nuclear bomb detonation in history

Unfortunately, the documentary is narrated in Russia, but The War Zone has a remarkably-detailed description of the events portrayed within, including this delightful description of the immediate aftermath of the explosion:

According to the video, the Tu-95V was 28 miles away from the release point, and the detonation produced a fireball visible 621 miles away, despite cloudy conditions. “The explosion was accompanied by a bright flash of unusual strength,” the narrator explains. Within seconds, a column of dust had risen to a height of around 6 miles. 

The footage then returns to the aircraft, at a distance of 155 miles from the detonation and we see the huge fireball, rising slowly and expanding to reach a maximum of 12 miles across. Forty seconds after the detonation, the fireball has reached a height of approximately 19 miles, after which a mushroom cloud begins to form, reaching a maximum height of 37-40 miles and a diameter of 56 miles.

You can watch the full documentary below, and read more at The War Zone here.