Castles in the New World?

This may already have been discussed... but to me, being European, it is bizarre to say the least to see castle-like buildings in the USA and even Australia. I do not count them as proper castles! Not only aren't they old enough, but they also lack the purpose for which castles in the Old World have been built. The American castles are merely follies: whimsical buildings that are meant for one thing only: to show off the wealth (and debatable taste!) of its owners. I am sorry but if these are to be considered real castles, well, then what is to stop anyone from adding the Disneyland castle to the list as well??? Just because something LOOKS LIKE a castle does not make it a castle.