Prince William and the Princess of Wales (formerly known as Kate Middleton) tied the knot on April 29, 2011, after several years of dating. The royal wedding of the future king and his bride was a grand affair and like something out of a storybook. It took place at Westminster Abbey in London with nearly 2,000 guests in attendance and millions more around the world who tuned in to see the couple say “I do.”

One of the most talked-about moments from that day had to do with what Kate wore. She stunned in an Alexander McQueen dress designed by Sarah Burton with a 16.5-foot-long silk tulle veil. She also donned pear-shaped diamond earrings and another accessory, worth more than $1 million, that still has people talking today.

Here’s more on that, plus something else the princess has sported on multiple occasions that can create some issues after it’s worn.

The accessory Kate wore that included a jaw-dropping 1,000 diamonds

When the now-Prince and Princess of Wales tied the knot, Queen Elizabeth II loaned Kate the Cartier Halo tiara. It has since become one of the most iconic royal wedding tiaras of all time.

The diamond experts at U.K. retailer Steven Stone delved into the history of the lovely diadem which was often considered “a good beginner tiara of sorts, perfect for a younger family member, with a smaller-than-average size that wouldn’t induce headaches.” It’s one that Queen Elizabeth II only wore once as she preferred to wear larger, grander pieces.

Maxwell Stone commented: “Fans around the world are captivated by the dazzling tiaras of the British royal family, and it’s no surprise — these iconic pieces are among the most valuable and historically rich jewels in the world.

One of the most unforgettable royal wedding tiaras is the Cartier Halo tiara, worn by the Princess of Wales on her wedding day. Worth approximately £1 million ($1.2 million), the tiara features 739 brilliant-cut diamonds and 149 baguette diamonds. Originally a gift from King George VI to Queen Elizabeth in 1936, it’s quite the favorite with the royal ladies and has been worn by Queen Elizabeth II, Princess Margaret, and Princess Anne — further cementing its place in royal history.”

One of the princess’s other favorite tiaras has been known to cause problems

Another tiara Kate favors is one her mother-in-law, Princess Diana, was also seen wearing several times and that is Queen Mary’s Lover’s Knot. Unfortunately, the particular diadem can cause problems for whoever wears it because of its weight.

According to celebrity stylist and fashion coach Miranda Holder, the gorgeous diamond and pearl Lover’s Knot has caused headaches for some ladies including Princess Diana who complained often about that after she had it on for the evening.

Holder told The Mirror: “Apparently because it was so heavy [Diana] used to get terrible headaches from wearing it.”

Holder added that another issue with the tiara is that it’s said to be very noisy due to the 19 swinging pear-shaped pearls.