This movie is about two couples (they were couples in real life too, and they used their real names), one from St. Louis and one from Switzerland. They each go to the other's country and travel around. That's the plot, such as it is - but seeing the sites in Cinerama is a lot of fun.
There are huge musical stage productions in Paris and Las Vegas, bobsledding, a county fair, skiing, a puppet show (where you can see the audience as well as the show) and a lot of more low-key stuff. It's a lot like being taken on vacation by interesting hosts. If you get the chance to see it, do.