Queen Elizabeth II beamed in a sunny yellow hat, designed by her assistant, Angela Kelly, that matched her sunny disposition. She's flanked by a festival of hats: on her new in-laws, the Middletons, down left; her daughter-in-law Camilla, down right; her husband Prince Philip at left; granddaughters Beatrice and Eugenie just behind, and daughter-in-law Sophie, wife of Prince Edward behind them.
Perhaps royals like hats so much because they're easier to wear than a crown.