@Gargron yeah see I'd call this a castle but it's close to the boundary. Maybe my decision criteria is wrong. I basically think turrets + rugged location = castle. Ramparts are an even surer sign. (getting dangerously close to "featherless biped" territory here)

Reading English wikipedia it seems like a palace is a luxuriant dwelling. while a castle is built to be defended. So I guess Neuschwanstein is technically a palace though it has been built in a Romantic style to look like a castle!