12. Princess Diana, 1981
A 20-year-old Diana Spencer wed Prince Charles at St. Paul's Cathedral in a stunning, now-iconic gown designed by David and Elizabeth Emanuel. Hand-embroidered with mother-of-pearl sequins and an estimated 10,000 pearls, the gown took the designers months to prepare. It also featured a 25-foot-long train, adorned with lace that once belonged to Queen Mary. For the special occasion, Diana wore her family's Spencer tiara. The Spencer tiara belongs to Princess Diana's family, who can trace their aristocratic lineage back to the Tudor period. It's also known that Queen Elizabeth II offered to loan the Lover’s Knot Tiara to the Princess of Wales on her big day. Both of Diana's sisters have also worn the timeless piece on their wedding days.