The director was given considerable freedom to complete the work, and was given much help from both the Soviet and Cuban governments. The film made use of many innovative techniques, such as coating a watertight camera's lens with a special submarine periscope cleaner, so the camera could be submerged and lifted out of the water without any drops on the lens or film. At one point, more than 1,000 Cuban soldiers were moved to a remote location to shoot one scene—this despite the then-ongoing Cuban Missile Crisis.