Hey the Rhone comes from the centre of Switzerland not just from lake Geneva! You should correct that, we are still such a tiny country don't take things away from us :)
Why? Why does someone's crossing of a river mean that it should be added to a quiz? Anyway, the river is very small and is unlikely to show up well on the map above - I don't suppose the practicalities and aesthetics of how it would appear on the map even crossed your mind.
Very good quiz, but as others have already commented, you could add some rivers as well. Bug, Evros/Maritsa, Guadalquivir, Guadiana, Axios/Vardar. I still don't understand what was the importance of Inn and Severn though, first time I've heard them,. Don't get me wrong, I've learn something useful at least.
Good quiz. Thanks.
Douro was accepted as a type-in, but still...
Great quiz thax.