The film was a significant undertaking, heavily supported by the Yugoslav government under . Tito, a fan of cinema who understood the propaganda and economic value of major international films, personally authorized the military to assist the production. This collaboration included:
: President Tito even visited the set during filming to meet the cast and crew. Iconic Regional Locations Force 10 from Navarone titlovi Hrvatski
: Nearly 2,000 Yugoslav soldiers were used as extras, particularly for the climactic battle scenes. The film was a significant undertaking, heavily supported