9. Grace Kelly
While Grace's first ring was nothing short of beautiful, the one that came next is a real show-stopper.

The second ring is a 10.48-carat emerald-cut diamond with two baguette-cut side stones, which was also made by Cartier. Rainier reportedly gave it to her when she was filming High Society, after learning that the costume designer was going to have her sport a large fake ring. We guess he figured she might as well just have the real thing.