Who owns the most expensive crown?

Could you please elaborate on the ownership of the most expensive crown? I'm intrigued to know who holds this prestigious title and the story behind it. Is it a royal family member, a private collector, or perhaps an institution? I'm also curious about the value of this crown and what makes it so expensive. Is it adorned with rare gems, intricate craftsmanship, or a combination of both? I'm eager to learn more about this fascinating piece of jewelry and its enigmatic owner.