Principal photography started on August 12, 1974, and ended in late September 1974. The picture was filmed on location on the Eiger mountain and Zurich in Switzerland, in Monument Valley and Zion National Park in the American Southwest, and in Carmel-by-the-Sea and Monterey in California. Special equipment and handheld cameras were employed to film the climbing sequences. Eastwood did his own climbing and stuntwork under dangerous conditions. Twenty-six-year-old British climber David Knowles died on the Eiger during the production. The film score was composed by John Williams.