In this sentence:
Sur son chemin, il trouve le pont de l'épée, une énorme épée posée entre deux rives comme un pont protégé par deux lions.
A lot of people, including the currently voted best translation, translated "rives" as "rivers". As far as I can tell, this is completely incorrect, but it seems like the only way to get the word out is to go through and put a note on each individual mistranslation...and I am too lazy. It also seems like as long as the best translation has this mistake, the problem will continue. What should we do? It would be great if Duolingo could implement some sort of crisis-response thing for common mistakes...this could be a major downside to the crowdsourcing model.
Anyway, Duolingo's dictionary defines "rive" as "shore," and my personal dictionary (Merriam-Webster) defines it as "bank (of a river)." The French word for "river" is "riviere" with an accent grave on the first e. (I'm having trouble figuring out how to add accents in comments/questions...)
Edit: Another word for "river" is "fleuve." Thanks, Arjofocolovi!
@anomalocaris - I wouldn't worry. Firstly, I don't think anyone knows that they have been downvoted (so I'm not sure how siebolt gives them a wake up call). Secondly, I took the trouble to write some Insights about specific bad translations, but clearly no-one has bothered to read them since. Although to be fair, they soon scroll off the horizon. Hence my Insight from yesterday: http://duolingo.com/#/comment/30627 So mark fairly, but mark harshly to get rid of these horrors.
You can also go through and quickly downrate every sentence that uses "river" in its translation. Click on "Show more translations" to get a list. When that stops working, close the sentence and re-open it. You will get further lists of sentences to rate, apparently selected at random. Eventually, you will be returned more sentences you have already rated than new ones, when it's time to give up. But I agree with your OP, the "best" translation is often garbage.