Sir Sean Connery, who received top billing, spent three weeks filming in Moscow. Peter Finch spent nine months on the production.
The script, based on Yuri Nagibin's novel of the same title, was adapted by Yuri Nagibin and Mikhail Kalatozov. Due to a series of conflicts with the producer, who insisted on expanding the role of his then wife Claudia Cardinale, Nagibin couldn't complete the script and it was completed by De Concini and Bolt.
The film features a disaster involving the famed Italian aviator Umberto Nobile (1885-1978). Nobile was blamed for a number of poor decisions leading up to the air disaster. At the time of the accident, he was suffering from sleep deprivation which likely impaired his cognitive functions. He was awake for at least 72 hours at the time of the accident.
Filming went for 62 weeks. It included location work in Estonia, the Baltic Sea and the Spitzbergen Archipelago in the Arctic Ocean, and studio work in Moscow and Rome. Shooting was completed on 12 April 1969.
This was the first co production between the Soviet Union and a Western country.