Where? Bosworth Field, at the foot of Ambion Hill in England.
Why is it famous? For being the site of the battle where Richard the Third was killed and the House of York defeated by Henry Tudor (later known as Henry the Seventh) and the House of Lancaster, thus ending the War of the Roses.
You can have the Crystal in exchange for 10 tickets now, Dr. Tropy.
EDIT: Dueling Book name is DinoRibbit, in case I decide to keep a Crystal later, or duel for one.