Palace.

I'm trying to figure out where my mind palace should be...obviously, the place I know best would be my own house, or possibly the school, but I would really like to have a place far more grand than that...

Perhaps I should use Hogwarts, I do know that place very well from my countless re-readings of the series, but that makes me feel like a copycat (even though it's a good fit). Considering I probably wouldn't be going there very much until school, I actually do have quite a bit of time to familiarize myself with a very grand place...I'm thinking Windsor Castle or Buckingham Palace. I'm edging towards Buckingham palace.

Windsor Castle

VS

Buckingham Palce