Royal Mad Hatters!

Long live the Queen and her coordinating hats! Her Royal Majesty turned her 2010 tour of Canada into one heady occasion, first debuting a hot pink-and-chartreuse number on July 3, before gathering a few feathers in her mauve-and-burgundy cap – deftly topped off with a pair of 3D glasses – two days later.

All eyes are on Prince Edward's wife Sophie – and her bouquet of roses (and circles and maple leaves) – as she takes in the races at Royal Ascot in June 2008.

When it comes to hats this young royal aims high, sky high. The 22-year-old daughter of Prince Andrew and Fergie shows off her love of gravity-defying headpieces, from the riotous butterfly colony by Philip Treacy she donned in May 2008 to the fanciful two-tone hat she wore at Ascot a month later.

The British press dubbed Beatrice's younger sister Eugenie, 21, "the princess and the green pea hat" for the Day-Glo green topper she donned at Royal Ascot in 2009 in celebration of Ladies' Day, which traditionally gives Britons a chance to show off their most, yes, outlandish hats.

It's the rose bowler parade! Prince Charles's wife Camilla puts her English garden on display in a floral wreath hat during the Queen's annual birthday parade at the Trooping the Colour in June 2008. A year later, she topped herself in something pretty in pink for a day at the races at Royal Ascot.

The siblings may share royal family ties, but when it comes to hats it's every sister for herself. The more unconventional Lady Davina (left) made a pleating appearance alongside her little sister Rose, who donned her namesake flower, during the wedding of fellow royal Peter Phillips in May 2008.

The 29-year-old daughter of Prince Michael of Kent tipped her feathered, wide-brimmed hat to her father's cousin, Queen Elizabeth, and Prince Philip in celebration of the couple's diamond wedding anniversary at Westminster Abbey in November 2007.

The Queen's daughter gives new meaning to the term royal mint in a pale green, lace-trimmed hat paired with an elegant, color-coordinated jacket as she made her grand arrival in a horse-drawn carriage at Ascot in 2009.

While mum Anne takes a low-key approach to headpieces, that's not the case for her equestrian daughter, who puts on a best in show on and off the field. After flaunting her wild side at Ascot in 2007, the 29-year-old proved she can be an equally demure English rose the following year at the races.