They actually danced under the bridge. Americans who brought the song home after WWII mistakenly changed "sous" to "sur". The bridge was far too narrow for people to dance in a ring on it.
Mae Klong should work as that is the true answer to the question asked; the river wasn't renamed the Kwai until after the popularity of the book/movie.
I was such an idiot on that clue. I kept thinking it was asking for the name of the movie. I typed variations of "Bridge on the River Kwai" for like 2 minutes. I rarely look things up while I'm taking quizzes, but I was so paranoid about it, I checked on Google. When Wikipedia told me that I was in fact typing the movie correctly, I looked back at the clue and realized it was asking for the river, not the movie name. *facepalm*
Among the many inaccuracies in Braveheart is that the Battle of Stirling Bridge somehow had no bridge in it, even though that was crucial to the outcome of the battle, But it would be easier to list what that movie got right than to catalogue all the things it got wrong.
I didn't realise that "The Bridges of Madison County" is a movie and neither did I realise that "stars" means actors, so I was confused which celestial bodies had something to do with those bridges...
The Tacoma bridge would be worth a question, this is the one that spectacularly collapsed due to an engineering mistake. And as a mathematician, I'm slightly disappointed that the seven bridges of Königsberg aren't mentioned.