One of those Duke Wayne movies ---

There were reports of some tension between the two stars. John Wayne was known for his traditional, no-nonsense approach to filmmaking, while Sophia Loren, being relatively new to Hollywood at the time, brought a different energy to the set.

Wayne was reportedly frustrated with Loren's European style and her sometimes flirtatious behavior, which clashed with his more straightforward and professional demeanor. However, despite these differences, they managed to complete the film without any major conflicts. Their professional attitudes ensured that any personal disagreements did not interfere significantly with the production.

Ultimately, while they may not have formed a close friendship, they were able to work together effectively to complete the film.

I hadn't seen this in quite a while. I remember not liking it very much way back then. But after a recent viewing, I can respect it more. Still don't quite like it but I think it's just okay. It's almost kind of refreshing as far as John Wayne movies go.
I like the lost city setting. It is very eerie and has this Indiana Jones vibe. Made even better knowing now that is an actual Roman ruins located in modern day Libya.
I think while all the performances are good enough and the on-location scenery is outstanding, the movie suffers from a noticeable lack of action.