If there were a contest for “biggest tiara in Europe,” I’d be hard pressed to think of another sparkler that could best this one. The Empire Tiara owned by the grand ducal family of Luxembourg is a massive diamond fortress of a jewel. At more than four inches tall, it’s a giant of the tiara world. Because of its size, the all-diamond tiara has plenty of room for the incorporation of numerous motifs, including geometric, anthemion, and scroll designs.