to June 14, 1966, nearly 53 years ago, and a pair of Danish princesses (who were 2nd cousins, once removed) arriving at Ascot. The glamorous Princess Marina, Duchess of Kent, wore a feather covered pillbox while a fresh-faced Princess Benedikte of Denmark wore a straw Breton hat.
Thanks for sharing any royal hats worn today in the comments as well.
Photo from Getty as indicated