[QUOTE 3972178, member: 259"]Isn't that one of those trick questions that depend on how you define a river and how you define a capital?[/QUOTE]
Yes, along with "founded" and "on"...
I think people who claim Madrid was not founded on a river do so on the basis that it was founded on a headland overlooking the river.
I think people who claim that Madrid is the highest Capital in Europe do so on the basis that Andorra is a Principality not a country so Andorra la Ville is not a capital city.
I think people who claim that Vatican City is not also a Capital not founded on a river do so on the basis that it was founded as Rome which was on a river and only later redrew boundaries which do not include a river. Or something.
They are all arbitrary definitions, just like whether Alaska contains territory further east than Maine...