Even though Middleton likely wishes she could burn all traces of photographic evidence, her infamous strut down a college catwalk will live in the history books forever. Only 20 years old, the Duchess-to-be wore a risqué, see-through dress in a 2002 charity runway show at St. Andrews University. The dress, possibly meant to be a skirt, left little to the imagination, and her undergarments were in plain view for everyone to see -- including Prince William, who watched the fashion show from a front-row seat. Although this skimpy garment would no doubt make the queen frown, it's rumored that the provocative outfit first caught the eye of the prince. In all the years since the fashion show, Middleton has never worn anything so revealing in public, and we can all agree that it's probably in good taste to keep underwear under wraps.