In the scene where Susan rides her birthday horse, Chulo, for the first time, there was a cameo by champion stud Captain Topper, a Shetland pony born in 1956. He was adjudged the greatest model stallion at the National Congress Pony Show in 1958 and 1959, and won 17 championships and 40 blue ribbons. Captain Topper was purchased for $6000 by Miss Patricia Burton of Detroit, who operated a stud farm on the Monterey peninsula.
Film rights to the novel were purchased by producer Edward Small in February 1960. He subsequently sold the rights to Warner Bros. The studio then assigned director Delmer Daves and cast Troy Donahue & Dorothy McGuire all who had previously collaborated in the very successful Ils n'ont que vingt ans... (1959).
The passenger liner the Slades are depicted as taking from Chile to California is the S.S. President Cleveland of the American President Line. Originally to built as a transport ship for the U.S. Navy in World War 2, her construction was started at the Bethlehem Steel Shipyard in Alameda, California in August 1944, but the order was canceled in December 1944. She was not completed as a passenger liner until 1947. She sailed trans-Pacific routes until she was scrapped in 1974.
During Susan's first make-out scene with Conn White, Max Steiner recycles his famous love theme from "A Summer Place" (1959). Oddly enough, the theme that leads into that famous theme on the "A Summer Place" soundtrack was recycled from his score to the Bette Davis vehicle, "A Stolen Life" (1946). Not only does the film borrow Steiner's "A Summer Place" theme it also borrows Troy Donahue and Dorothy McGuire from the film.
The United Airlines aircraft shown when the Slades leave for Guatemala is a 1952 Convair CV-340-31, registration N73109. It flew with United until 1969, then with several smaller airlines until 1995 when it was withdrawn from service and stored. It's registration expired in 2012.