The film, The Conqueror was financed by Howard Hughes who was so embarressed about how bad it was he spent $12million buying every copy and refused to let it be shown anywhere. It finally got a release in 1974.
However the real tragedy is that the film was shot on a nuclear test ground and the main stars, John Wayne, Susan Hayward, Agnes Moorhead, and John Hoyt plus Dick Powell, the director, all died from Cancer. Pedro Armendariz, who also starred in the film commited suicide after being diagnosed with terminal cancer.
Hughes in fact paid for the soil from the test area to be imported into Holywood for all the retakes.