The film is set in the Panama Canal Zone (1903-1979), an unincorporated territory of the United States. The territory consisted of the Panama Canal itself and a surrounding area of 5 miles (8 kilometers) on each side of the center-line. The area was granted to the United States by the Republic of Panama through the Isthmian Canal Convention (1904). The United States returned the area to Panama,, through the Torrijos-Carter Treaties (1977).